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

[Subrata Banik (Code Review)]

Attention is currently required from: Nico Huber, Krishna Prabhakaran, Furquan Shaikh, Maulik V Vaghela, Selma Bensaid, Meera Ravindranath, Patrick Rudolph.
Subrata Banik 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/d850b686_b7ac7b01 
PS13, Line 105: INTEL_GMA_OPREGION_2_0
> I would recommend to make 2. […]
> > What determines this support? Isn't this just something that the kernel driver needs to support?

yes, you are right. If we drop support for 2_0, then it has to be communicated and what is the expectation also needs to call out. I guess we have some data on that too. @meera, wasn't there a display issue when we are passing 2_0 and driver expects 2_1?
> > Or are there other factors? If it is just the kernel driver dependency, would it make sense to announce this deprecation in coreboot and drop support for 2.0 in next 6-12 months?

Yes, better to take that call into sometime from now as you said 6-12month and we notify others. Thoughts ?