google/gru: Incorporate feedback to #14279
To avoid diverging too much on an actively developed code base, keep
the changes to a separate commit that can be downstreamed more easily:
- removed unused includes
- gave kevin board a "Kevin" part number
- marked RW_LEGACY as CBFS region (to follow up upstream changes)
- moved romstage entry point to SoC code (instead of encouraging
per-board copy pasta)
Change-Id: Ief0c8db3c4af96fe2be2e2397d8874ad06fb6f1f
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: https://review.coreboot.org/14362
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>