[M] Change in coreboot[main]: tree: Use boolean for s0ix_enable

[Angel Pons (Code Review)]

Attention is currently required from: Christian Walter, Dinesh Gehlot, Elyes Haouas, Eran Mitrani, Eric Lai, Jakub Czapiga, Jason Nien, Jayvik Desai, Jeremy Soller, Jonathon Hall, Kapil Porwal, Lean Sheng Tan, Martin Roth, Michael Niewöhner, Michał Żygowski, Nick Vaccaro, Patrick Rudolph, Piotr Król, Rishika Raj, Subrata Banik, Tarun, Tim Crawford, Werner Zeh.

Angel Pons has posted comments on this change by Elyes Haouas. ( https://review.coreboot.org/c/coreboot/+/84159?usp=email )

Change subject: tree: Use boolean for s0ix_enable
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Patch Set 1: Code-Review+2

(1 comment)

File src/mainboard/google/brya/variants/baseboard/nissa/devicetree.cb:

https://review.coreboot.org/c/coreboot/+/84159/comment/8175a381_6c44ee20?usp... :
PS1, Line 34: # DPTF enable
            : 	register "dptf_enable" = "1"
For another patch: this one can also be a bool