Patch merged into coreboot/master: i945: Enable changing VRAM size

the following patch was just integrated into master:
commit 874a8f961ff537bc12cfca3d9937a07fcda2fe6e
Author: Arthur Heymans 
Date:   Thu May 19 16:06:09 2016 +0200

i945: Enable changing VRAM size

On i945 the vram size is the default 8mb. It is also possible
    to set it 1mb or 0mb hardcoding the GGC register in early_init.c

The intel documentation on i945, "Mobile Intel® 945 Express Chipset
    Family datasheet june 2008" only documents those three options.
    They are set using 3 bits. The documententation also makes mention
    of 4mb, 16mb, 32mb, 48mb, 64mb but not how to set it.

The other non documented (straight forward) bit combinations allow
    to change the VRAM size to those other states.

What this patch does is:
    - add those undocumented registers with their respective vram size to
    the i945 NB code;
    - make this a cmos option on targets that have this northbridge.

TEST: build, flash to target, set cmos as desired and boot linux.
    On Debian it can be found using "dmesg | grep stolen".
    NOTE: dmesg message about reserved vram are quite different depending
    on linux version

Change-Id: Ia71367ae3efb51bd64affd728407b8386e74594f
    Signed-off-by: Arthur Heymans 
    Reviewed-on: https://review.coreboot.org/14819
    Tested-by: build bot (Jenkins)
    Reviewed-by: Martin Roth

See https://review.coreboot.org/14819 for details.

-gerrit