1. Add IGD opregion initialization.
2. Use frame buffer return by FSP for display.
3. Derived from "src/soc/intel/apollolake/graphics.c" with changes
needed for CNL.
TEST=Pre-OS screen comes up and VBT is getting passed to kernel.
Change-Id: I19c0cf6cfc03fc9df9e98c75af4e486cb5a19e32
Signed-off-by: Abhay Kumar <abhay.kumar@intel.com>
Reviewed-on: https://review.coreboot.org/21999
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
