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, Angel Pons, 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 19:

(4 comments)

File src/drivers/intel/gma/opregion.h:

https://review.coreboot.org/c/coreboot/+/52758/comment/a1447570_c922c05c 
PS14, Line 20: u32	version;
> I think we should update this to match how kernel (and the spec) defines this: […]

Done

https://review.coreboot.org/c/coreboot/+/52758/comment/440d5b3b_3db46f1b 
PS14, Line 145: Physical address of Raw VBT data
> This needs update. […]

Done

File src/drivers/intel/gma/opregion.c:

https://review.coreboot.org/c/coreboot/+/52758/comment/fceb54ba_002e6e54 
PS14, Line 271: if (CONFIG(INTEL_GMA_OPREGION_2_1))
              : 		return 0x201;
              : 
              : 	return 0x200;
> Another approach is to return a struct, but one needs to expose the struct type: […]

Done

https://review.coreboot.org/c/coreboot/+/52758/comment/8e3838e1_ac3554fa 
PS14, Line 288: 2.0
> 2.1 […]

Done