v4.0.1

• introduce versioning
• obtain smbios fields, such as board serial and SKU
• reduce log level: display mainboard, DRAM and ECC info only
• improve SD card performance
• force to use SD in 2.0 mode
• nct5104d driver backport
• check if git exists before calling it
• change git repository in Makefile
• add missing cbfs_find_string in libpayload
• add executable bit to xcompile