[S] Change in coreboot[main]: mb/google/brya: Add support to get sku ID

[Subrata Banik (Code Review)]

Attention is currently required from: Aamir Bohra, Dinesh Gehlot, Eric Lai, Jayvik Desai, Kapil Porwal, Nick Vaccaro.

Subrata Banik has posted comments on this change by Aamir Bohra. ( https://review.coreboot.org/c/coreboot/+/86599?usp=email )

Change subject: mb/google/brya: Add support to get sku ID
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Patch Set 3:

(1 comment)

Patchset:

PS2:
> Is there something for google mainboard common?

let me ask, I assume you are planning to add skuid implementation for CrOS devices alone ? if yes, then you can do something like this

1. Add choice menu for SKUID (CONFIG_CROS_SKUID) selection between CONFIG_SKUID_VIA_CHROMEEC or CONFIG_SKUID_VIA_ADC_PIN
2. if CONFIG_CROS_SKUID is enabled add sku_id.c inside vendor code (or else where as applicable)
3. Inside sku_id.c you can keep two implementation 
   - retrieve skuid using CrEC
   - retrieve skuid using ADC PIN
4. Then allow the main boards to choose how they wish to support SKUID (like HAVE_SKUID_VIA_CHROMEEC or HAVE_SKUID_VIA_ADC_PIN).

I assume non-CrOS main board doesn't fill or implement SKUID() function so, we won't impact those