baytrail: initialize graphics before MRC

The graphics device needs to have its resource contraints
initialized before running the reference code. Right now just
use a 256MiB aperture, 32MiB of stolen memory data, and 2MiB
GTT memory.

BUG=chrome-os-partner:22869
BRANCH=None
TEST=Built and booted. Noted amount of stolen memory matches
     configuration as well as BAR size within the graphics
     device.

Change-Id: I328bf858f288363187cf705d6340947393b5ff10
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170427
5 files changed