region: add rdev_chain_full()
Instead of open coding an offset of 0 and querying the size of a
region device provide a rdev_chain_full() helper function that
does that for the caller. For the existing users that match this pattern
convert them to using rdev_chain_full().
Change-Id: Ie316790a8a5b16a7f7e22f86f58bd2e633c19450
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36683
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>