ryu: add display operations

Provide display operations to vboot. Initialize the
display when directed as well as provide backlight
control. Lastly disable the display prior to handing
off control to the kernel.

BRANCH=none
BUG=chrome-os-partner:31936
TEST=Built and verified dev screen is shown as well as display
     working in the kernel.

Change-Id: I859b75fc7b8b2a5ae2d10d566d2b25596c09dacd
Signed-off-by: Jimmy Zhang <jimmzhang@nvidia.com>
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/228896
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
1 file changed