Change in coreboot[master]: drivers/intel/gma: Support IGD Opregion 2.1

[Meera Ravindranath (Code Review)]

Attention is currently required from: Nico Huber, Krishna Prabhakaran, Furquan Shaikh, Maulik V Vaghela, Selma Bensaid, Subrata Banik, Patrick Rudolph.
Meera Ravindranath has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/52758 )

Change subject: drivers/intel/gma: Support IGD Opregion 2.1
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Patch Set 13:

(1 comment)

File src/drivers/intel/gma/Kconfig:

https://review.coreboot.org/c/coreboot/+/52758/comment/ef79461e_85533544 
PS13, Line 105: INTEL_GMA_OPREGION_2_0
> > > What determines this support? Isn't this just something that the kernel driver needs to support?  […]
> >
> > @meera, wasn't there a display issue when we are passing 2_0 and driver expects 2_1?

Yes Subrata, So here is the details -

Linux kernel VFIO IGD driver would expose Opregion for guest VM. Current coreboot  uses opregion 2.0 for extended VBT, which causes problem for VM passthrough as the VFIO IGD driver only supports Opregion 2.1+

Pasting a snippet of the log that comes with the mismatch of versions

vfio-pci 0000:00:02.0: Extended VBT does not follow opregion on version 0x0201
vfio-pci 0000:00:02.0: Failed to setup Intel IGD regions
[ERROR:src/main.rs:2003] crosvm has exited with error: The archikvm: exiting hardware virtualization
tecture failed to build the vm: error creating devices: Failed to create vfio device failed to get vfio device fd: Invalid argument (os error 22)
reboot: Restarting system