Change in coreboot[master]: soc/intel/common: Configure TCSS access through IOE P2SB

[Paul Menzel (Code Review)]

Attention is currently required from: John Zhao, Eric Lai, Angel Pons, Patrick Rudolph, EricR Lai.
Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/62723 )

Change subject: soc/intel/common: Configure TCSS access through IOE P2SB
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Patch Set 3:

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/62723/comment/1ed8696b_d7894950 
PS2, Line 9: This change abstracts the TCSS access through IOE P2SB on Meteor Lake.
> Apart from the existing common code Kconfig _TCSS_REG_ACCESS_REGBAR, this change only adds the TCSS  […]

I still do not fully understand, why the common code needs to be adapted, and what changed in Meteor Lake. But I let more knowledgable people review.