Set up IGD OpRegion in northbridge and fill in GNVS' aslb.
At this point GNVS already has been set up by SSDT injection.
Required for future VBT patches that will:
* Use ACPI memory instead of CBMEM
* Use common implementation to locate VBT
* Fill in platform specific values
Change-Id: I97c3402ac055991350732e55b0dda042b426c080
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/19310
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
281ccca373