[coreboot] Can we get rid of SMMSTORE_IN_CBFS?

[Julius Werner]

As I'm trying to port all existing CBFS uses to the new APIs that
support verification, the CONFIG_SMMSTORE_IN_CBFS option is a bit of a
problem: It's the only CBFS use case where coreboot is actually trying
to write back into CBFS, and thus needs access to the raw flash
offsets of files (which is something I'm trying to stop from leaking
out of the abstraction).

Does anyone still need this? As far as I know it was just a hack
invented to backport SMMSTORE onto a Chromebook that couldn't make
FMAP changes anymore, and we never ended up using it after all. Anyone
still using SMMSTORE today should be putting it in a separate FMAP
section. Would anyone mind if I just remove the CBFS option?