Change in coreboot[master]: mb/prodrive/hermes: Fix PCIe ClkSrc configuration

[Angel Pons (Code Review)]

Attention is currently required from: Patrick Rudolph, Christian Walter, Michael Niewöhner.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/58065 )

Change subject: mb/prodrive/hermes: Fix PCIe ClkSrc configuration
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Patch Set 2:

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/58065/comment/ff78c778_bd93e2f1 
PS2, Line 10: Apparently, FSP does not turn off unused PCIe clock sources when using
> That could be, but I still don't get why this is mentioned as the ClkSrc configuration ist invalid f […]

Yes, the ClkSrc configuration in FSP UPDs is wrong. However, it wasn't noticed until now because the clock sources don't get disabled when running SPS firmware. After trying to use CSME firmware, the issue became apparent.

I can omit this reasoning if it's not necessary.