[S] Change in coreboot[main]: mb/google/brya: Create a tivviks variant

[V Sowmya (Code Review)]

Attention is currently required from: Dinesh Gehlot, Eric Lai, Kapil Porwal, Nick Vaccaro, Subrata Banik.

V Sowmya has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/81262?usp=email )

Change subject: mb/google/brya: Create a tivviks variant
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Patch Set 1:

(4 comments)

Patchset:

PS1:
> I am slightly perplexed. […]

Yes, Tivviks is a SKU reference/refresh of Nivviks with TWL silicon. I initially thought about the approach of using the Nivviks by switching to TWL SOC/IFWI but due to the following reasons we decided to create a new variant Tivviks which will leverage the Nivviks code with TWL SOC/IFWI,
1. Until all the IFWI components are completely converged for ADL-N/TWL with required quality checks, there is need to maintain Nivviks (ADL-N SOC/IFWI) and add the support for Tivviks (TWL SOC/IFWI). 
2. There is need to manage both the ADL-N (IPU) platform and Twinlake (execution) platform, so its recommended to maintain the builds/variants separately for both ADL-N and converged IFWI until these two are merged.

Yes, we can stop support for Tivviks by updating Nivviks to use the converged firmware for both ADL-N/TWL SOC, post complete validation of the firmware and availability of the external releases.

File src/mainboard/google/brya/Kconfig:

https://review.coreboot.org/c/coreboot/+/81262/comment/cda681a9_6c743376 :
PS1, Line 463: 	select SOC_INTEL_TWINLAKE
> please follow the alphabetic order

Acknowledged

https://review.coreboot.org/c/coreboot/+/81262/comment/88f35ebd_35118b72 :
PS1, Line 581: BOARD_GOOGLE_TIVVIKS
> please make a separate entry

Acknowledged

https://review.coreboot.org/c/coreboot/+/81262/comment/b4a3609c_ea9a9a7d :
PS1, Line 665: BOARD_GOOGLE_TIVVIKS
> why not use `Tivviks` as MAINBOARD_PART_NUMBER ?

Acknowledged