Patch merged into coreboot/master: nb/i945, gm45, x4x/gma.c: fix unsigned arithmetics

the following patch was just integrated into master:
commit 75f9131453c0e046f69ab4a8db7a3af7efcf6038
Author: Arthur Heymans 
Date:   Wed Oct 12 01:04:28 2016 +0200

nb/i945,gm45,x4x/gma.c: fix unsigned arithmetics

This issue was found by Coverity Scan, CID 1364118.

Change-Id: Iba3c0f4f952729d9e0987d928b63ef8b8fe8841e
    Signed-off-by: Arthur Heymans 
    Reviewed-on: https://review.coreboot.org/16992
    Reviewed-by: Martin Roth 
    Tested-by: build bot (Jenkins)

See https://review.coreboot.org/16992 for details.

-gerrit