[XS] Change in coreboot[main]: mb/google/brox/var/greenbayupoc: Add fw_config field for storage

[Ivan Chen (Code Review)]

Attention is currently required from: Eren Peng, Nick Vaccaro, Shelley Chen.

Ivan Chen has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/81833?usp=email )

Change subject: mb/google/brox/var/greenbayupoc: Add fw_config field for storage
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Patch Set 2:

(1 comment)

Patchset:

PS2:
> I feel like this would be confusing to people, having some fw_configs in baseboard and some in the a […]

Just want to clarify how we would like to manage it on brox.

Nissa defines the common fw_config as https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/thir... and leave the optinal field being defined freely by partner via boxster setting. I am thinking that we could move it to baseboard since if the field is used by default in depthcharge, we don't need all variants define it redundantly.