[XS] Change in coreboot[main]: mainboard/google/rex: Enable Rex64 build configuration

[Lean Sheng Tan (Code Review)]

Attention is currently required from: Eran Mitrani, Felix Held, Felix Singer, Jakub Czapiga, Martin L Roth, Paul Menzel, Subrata Banik, Tarun.

Lean Sheng Tan has posted comments on this change by Subrata Banik. ( https://review.coreboot.org/c/coreboot/+/82625?usp=email )

Change subject: mainboard/google/rex: Enable Rex64 build configuration
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Patch Set 9:

(1 comment)

Patchset:

PS7:
> > Build is successful https://qa.coreboot.org/job/coreboot-gerrit/258212/console but stil no V+1 […]

Jenkins was acting up, and that's where those V+1 are coming from. 
Felix S. restarted Jenkins.