Change in coreboot[master]: soc/intel/elkhartlake: Introduce Intel PSE

[Michael Niewöhner (Code Review)]

Attention is currently required from: Arthur Heymans, Maulik V Vaghela, Mario Scheithauer, Subrata Banik, Lean Sheng Tan, Werner Zeh, Patrick Rudolph, Felix Held.
Michael Niewöhner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/55367 )

Change subject: soc/intel/elkhartlake: Introduce Intel PSE
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Patch Set 43:

(1 comment)

Patchset:

PS43: 
To me it seems that PSE is optional. Comments in reference code claim that PSE can be either fused disabled or set disabled by "Policy" (= UPD). There is a UPD `PchPseEnable` that defaults to 1, leading to the described reset loop, without providing PSE firmware like done in this change.

That means: PchPseEnable should be set and probably a Kconfig should be added, just like for FSP. This way, enabling PSE and providing a blob can be optional.