[XS] Change in coreboot[main]: soc/intel/mtlrvp: use different names for mtlrvp variants

[Angel Pons (Code Review)]

Attention is currently required from: Kapil Porwal, Paul Menzel, Subrata Banik, YH Lin.

Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/82084?usp=email )

Change subject: soc/intel/mtlrvp: use different names for mtlrvp variants
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Patch Set 5: Code-Review+2