CSM No Longer Required in ChubbyAnt Fork - Compatibility Support Mode

[ChubbyAnt]

The https://SEDutil.com / https://github.com/ChubbyAnt/sedutil version of SEDutil no longer requires CSM support, and now works cleanly (without the need for nomodeset) with AMD Ryzen systems.

@oom-is created a pull request (#306) updating the buildroot target to 2019.02.6 (latest LTS buildroot2) and the Linux kernel to 4.14.146 (latest kernel in that 4.14 LTS series). This PR has been merged with the https://github.com/ChubbyAnt fork, which is a SHA2 / 512 fork of SEDutil.

The (#306) PR removes the need for CSM support, and also fixes the glibc / m4 build error (ChubbyAnt#7) that has been popping up recently.

Thank you, @oom-is!