Change in coreboot[master]: soc/intel/common: Add InSMM.STS support

[Patrick Georgi (Code Review)]

Attention is currently required from: Nico Huber, Patrick Rudolph, Benjamin Doron, Paul Menzel, Arthur Heymans, Michael Niewöhner.
Patrick Georgi has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/51796 )

Change subject: soc/intel/common: Add InSMM.STS support
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Patch Set 11:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/51796/comment/df0540ec_168d6e34 
PS3, Line 9: Tested on HP 280 G2, SMMSTORE (v1) still works.
> Good question

Ack

Commit Message:

https://review.coreboot.org/c/coreboot/+/51796/comment/8b2b7456_8c1be2a2 
PS9, Line 13: - If one does not write the magic MSR `or 1`, SMMSTORE breaks.
> I didn't use this document.

Ack

File src/soc/intel/common/block/smm/smihandler.c:

https://review.coreboot.org/c/coreboot/+/51796/comment/6f513648_80649505 
PS9, Line 268: 0xfed30880
> Various Intel documents reference this by Magic Hex value TM only. […]

Ack