Change in coreboot[master]: soc/intel/skylake: Ensure FSP don't override ITSS IPCx registers

[Michael Niewöhner (Code Review)]

Michael Niewöhner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/28791 )

Change subject: soc/intel/skylake: Ensure FSP don't override ITSS IPCx registers
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Patch Set 3:

@Nico cnl seems to have problems, too. see TODO comment in src/soc/intel/cannonlake/chip.c:143