google/lulu,gandof: set kb backlight on boot

Set keyboard backlight to 75% on boot, except when resuming
from S3.  This enables the backlight at a reasonable level
prior to the OS driver taking over, providing early proof-of-life
and enhanced usability in grub etc.

Uses same method as other google boards with a keyboard backlight
(chell, link, samus).  75% value determined based on user feedback.

TEST: boot google/lulu,gandof boards, observe keyboard backlight
enabled in pre-OS environment.

Change-Id: I7ed59289419af21764b1b5bd0a534d3b630c6c6b
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/21330
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
2 files changed