Patch merged into coreboot/master: commonlib: Add function to compute relative offsets from two region_devices.

the following patch was just integrated into master:
commit 990ab7efe5d0eddb96542042bf5106811365e34a
Author: Aaron Durbin 
Date:   Tue Dec 15 13:29:41 2015 -0600

commonlib: Add function to compute relative offsets from two region_devices.

Provide a helper function which returns the relative offset
    between 2 region_devices that have a parent-child child relationship.

BUG=chrome-os-partner:48412
    BUG=chromium:445938
    BRANCH=None
    TEST=Utilized and booted on glados.

Change-Id: Ie0041b33e73a6601748f1289e98b6f1f8756eb11
    Signed-off-by: Aaron Durbin 
    Reviewed-on: https://review.coreboot.org/12782
    Tested-by: build bot (Jenkins)
    Reviewed-by: Martin Roth 
    Reviewed-by: Patrick Georgi

See https://review.coreboot.org/12782 for details.

-gerrit