This reverts commit fe2b72035fb58d2c0792daa62aa346da710f04a3.

The GRUB patch to fix the E6400 broke other systems and has been
reverted. As a result, GRUB needs to be disabled again on the E6400
until a better fix has been created.

This reverts commit 1497ae045104145de677fd151da4de6e92be4e5a.

The blanket GRUB patch seems to break PS/2 keyboard handling across
other platforms, so revert it.

This reverts commit 7bc4dc32ac3e430e50ace3a2876cf501f647b89f.

The E6400 keyboard should work in GRUB now so we can reenable it.

This introduces a patch to grub which disables the coreboot
specific handling, allowing PS/2 keyboards to be handled the
same as i386-pc.  However this alone breaks the keyboard in
Linux, requiring coreboot to perform PS/2 initialization.

I think GRUB may be restoring the original configuration of
the PS/2 controller once it exits, and if coreboot doesn't
initialize the controller then it's restored to the default
state which Linux doesn't seem to like. I think the emulated
keyboard interface provided by the EC on the E6400 behaves
in a non-standard way that is incompatible with the old
coreboot specific handling.

ps/2 internal keyboard faulty in grub target
i386-coreboot, according to nic3-14159

normal i386-pc grub (bios grub) is fine,
booted from seabios

it is being investigated

Tested the 4MiB ROMs but not the 8 or 16 MiB ones. This uses the same
board.cfg as the GM45 ThinkPads with an IFD+GBE from ich9gen.

Known issues:
- The internal keyboard does not work properly in GRUB. It seems like
  the keyboard controller is outputing set 1 (XT) scancodes, but GRUB
  is interpreting them as set 2 (AT) scancodes. This may also have
  something to do with scancode translation. However, the keyboard works
  fine in SeaBIOS and Linux. USB keyboards also work properly.
- The subsystem IDs in the GBE region are hardcoded for a Thinkpad in
  ich9gen, though this doesn't seem to cause issues in Linux. The vendor
  IFD and GBE region do have some differences from the generated
  binaries, though they do not appear to be critical.

libreboot will still include microcode updates
by default, but mitigations against broken speedstep
and reboot (when microcode updates are excluded) were
removed following the merge with osboot

this patch restores those mitigations; the patch
reverts coreboot to older smrr code (which works fine, it
isn't critical to use the new behaviour) and disables peci
(pointless feature)

i'll probably re-tool this later to apply the changes
conditionally to whether ucode is present

this is not a change in policy. policy says:
include cpu microcode updates by default

policy also says:
libreboot must be configurable

microcode removal via cbfstool remove -n, counts as
configuration, and in practise is not possible on
gm45 patches in current libreboot; this patch corrects
that problem, allowing the machines to work somewhat
well (same stability issues as before, like MCE errors
resulting in kernel panic on high CPU/memory usage,
but i digress)

happy... hacking