[coreboot-gerrit] [M] Change in coreboot[master]: mb/google/rex: Create karis variant

[Tyler Wang (Code Review)]

Attention is currently required from: Kapil Porwal, Paul Menzel, Subrata Banik, Tarun Tuli.

Tyler Wang has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/75551?usp=email )

Change subject: mb/google/rex: Create karis variant
......................................................................

Patch Set 4:

This change is ready for review.