ramstage_cache: allow ramstage usage add valid helper

Allow ramstage cache to be used from ramstage proper. Also
add a helper function for checking validity of ramstage
cache structure.

BUG=chrome-os-partner:22867
BRANCH=None
TEST=Built and booted. S3 resumed.

Change-Id: If1f2ad1bcf64504b42e315be243a12432b50e3d5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/179775
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/5011
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
2 files changed