[coreboot-gerrit] Patch merged into coreboot/master: commonlib: provide incoherent region device

the following patch was just integrated into master:
commit 256db40b14ea6b9e587f99106994e54a24e21d7f
Author: Aaron Durbin 
Date:   Sat Dec 3 17:08:08 2016 -0600

commonlib: provide incoherent region device

The MRC cache uses an incoherent mechanism for updating the
    cache contents in that it assumes memory mapped boot device
    access for checking against latest data for update. However,
    it uses another driver for updating the underlying storage
    area.

In order to aid in moving the MRC cache over to using
    region_devices for updates provide an implementation of
    a region_device which performs reads and writes to different
    region_devices so that different drivers can be used
    transparently.

BUG=chrome-os-partner:56151

Change-Id: I30e858245c30cbccd6313aff5ebecd3fd98d7302
    Signed-off-by: Aaron Durbin 
    Reviewed-on: https://review.coreboot.org/17716
    Tested-by: build bot (Jenkins)
    Reviewed-by: Furquan Shaikh 
    Reviewed-by: Duncan Laurie

See https://review.coreboot.org/17716 for details.

-gerrit