libpayload: Minor board ID / RAM code cleanups

This patch mirrors recent cleanups in coreboot regarding the strapping
ID entries in the coreboot table.

Change-Id: Ia5c3728daf2cb317f8e2bc72c6f1714d6cb4d080
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/22742
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
3 files changed