gma: Add G45 support

The following ports are implemented: HDMI/DVI, VGA, LVDS and DP.

Tested with gfx_test and coreboot on a Thinkpad X200 (GM45).

Change-Id: Ifc05a1516329a61772af84558e5bfceb4d4ca277
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/21295
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: Nico Huber <nico.h@gmx.de>
diff --git a/common/hw-gfx-gma.ads b/common/hw-gfx-gma.ads
index c35c687..fb5c7e5 100644
--- a/common/hw-gfx-gma.ads
+++ b/common/hw-gfx-gma.ads
@@ -30,7 +30,8 @@
 is
 
    type CPU_Type is
-     (Ironlake,
+     (G45,
+      Ironlake,
       Sandybridge,
       Ivybridge,
       Haswell,