LTS update for Buildroot and Linux Kernel

This pull request updates:
  Buildroot2 to the 2019.02.6 (latest LTS) target
  Linux Kernel to the 4.14.146 (latest version in 4.14.x LTS tree) version
  Other incidental updates along the way (binutils 2.30.x, GCC 8.3.x)

A longer explanation of why this update and how to do further updates is
in README_LTS.txt.

This update addresses several issues with USB input handling in linuxpba,
support for AMD Ryzen 2xxx and 3xxx chips, and other minor items.

This pull request is explicitly under the GPL 3.0 license, as is implicitly
required by Github's latest "inbound = outbound" license updates as discussed:
  https://ben.balter.com/2018/01/02/why-you-probably-shouldnt-add-a-cla-to-your-open-source-project/
  https://help.github.com/articles/github-terms-of-service/#6-contributions-under-repository-license
As always, differing opinions are encouraged; c.f.
  https://writing.kemitchell.com/2018/01/06/CLAs-Are-Not-a-Sham.html

This pull request should apply as-is for most current "unofficial" source
trees as it only affects certain files, which should not conflict with most
other known patch sets:

	new file:   README_LTS.txt
	modified:   images/buildpbaroot
	modified:   images/buildroot/32bit/.config
	modified:   images/buildroot/32bit/kernel.config
	new file:   images/buildroot/32bit/local.mk
	modified:   images/buildroot/64bit/.config
	modified:   images/buildroot/64bit/kernel.config
	new file:   images/buildroot/64bit/local.mk
	modified:   images/conf

README_LTS.txt

@@ -0,0 +1,74 @@
+This patch to Drive-Trust-Alliance/sedutil provides the following updates:
+  - Update Buildroot2 to 2019.02.6 (latest LTS version as of 14 October).
+  - Update linux kernel version to 4.14.146 (4.14.x and 4.17.x are current LTS
+    release streams.)
+
+The primary driving requirements for this were:
+  1.  Move to an LTS kernel version with the expectation that this could
+      fix some issues with USB support in the linuxpba utility, as well as
+      providing better support for newer Intel and AMD chips (particularly
+      Ryzen 2xxx and 3xxx chips).  ==> Yes, this update fixes those issues.
+  2.  Move to a Linux kernel version that allows compilation with Gnu GCC 8
+      and supports the full set of Spectre/Meltdown fixes.  For some of us
+      who might want to use SEDutil in an enterprise environment, it's
+      easier to be able to clearly state that Spectre fixes are present,
+      than to explain why there's really no attack surface from the older
+      Linux kernel
+  3.  Move incrementally to the "next" Linux LTS kernel, rather than the
+      absolute newest, given that the 4.11.8 kernel was a much older vintage.
+
+Along the way with Linux kernel updates, there were two other discoveries
+that affected the final upgrade path:
+  A.  It turns out Buildroot2 also has LTS versions, specifically the 20xx.02
+      releases are the LTS ones.  My original selection was 2018.08 but that
+      turned into 2019.02 in order to get to an LTS buildroot.
+  B.  As of 2018.11-rc1 SEDutil became an "official" part of Buildroot2 -
+      which means that when building newer Buildroot2 versions/targets, it
+      becomes necessary to override the Buildroot2 "official" source for
+      SEDutil with our own updated/customized tarball.  (Otherwise we end
+      up with DTA SEDutil plus Buildroot2 patches but no other local
+      patches that might be intentional/needed...)
+
+For anyone who wants to experiment with a newer Buildroot2 version or Linux
+kernel version:
+  - Buildroot2 target version is determined by images/conf
+    Any changes to the Buildroot2 target version may require a new buildroot
+    .config file to be created.  The actual files from the source tarball are
+    kept in images/buildroot/{32,64}bit/.config but making changes to them
+    should properly be done by:
+         execute "./buildpbaroot" the normal way from the images directory
+	 cd scratch/buildroot/32bit
+	 make menuconfig
+	   [Make any changes as needed]
+         cd ../64bit
+ 	 make menuconfig
+	   [Again, make any changes as needed]
+         cd ..
+         make O=32bit
+         make O=64bit
+	   [Now do whatever testing you believe is needed for the resulting
+            output]
+	   [Once you're happy, make sure you save those new 32bit/.config
+	    and 64bit/.config files somewhere, so you can use them again
+	    in the future.]
+  - Linux kernel version is determined by a config line in the buildroot
+    .config files above; however updating to a newer Linux kernel may
+    require new kernel.config files.  Changes of that sort can be 
+    accomplished similar to what's shown above:
+	 execute "./buildpbaroot" the normal way from the images directory
+	 cd scratch/buildroot/32bit/build/linux-4.14.146
+	 make menuconfig
+	   [Make any changes as needed]
+         cd ../../../64bit/build/linux-4.14.146
+ 	 make menuconfig
+	   [Again, make any changes as needed]
+         cd ../../..
+         make O=32bit
+         make O=64bit
+	   [Now do whatever testing you believe is needed for the resulting
+            output kernels]
+	   [Once you're happy, make sure you save those new .config files
+	    for 32bit and 64bit kernels somewhere as 32bit/kernel.config
+	    and 64bit/kernel.config, so you can use them again
+	    in the future.]
+

images/buildpbaroot

@@ -36,7 +36,16 @@ make dist
 mkdir images/scratch/buildroot/dl/
 cp sedutil-*.tar.gz images/scratch/buildroot/dl/
 make distclean
-cd images/scratch/buildroot
+
+# Expand the distribution tarball so we can use it as the Buildroot override.
+# Override location is specified in the 'local.mk' file in buildroot/{32,64}bit
+# directories.
+# See also section 8.12.6 "Using Buildroot during development" in the
+# Buildroot user manual.
+cd images/scratch/buildroot/dl
+tar xvfz sedutil-*.tar.gz
+cd ..
+
 # build the rootfs for 64 and 32 bit systems
 echo Building bootable systems for the PBA, this is going to take a while ..... Press enter to continue
 read INOUT