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-config_helpers.adb b/common/hw-gfx-gma-config_helpers.adb
index 5e5be5d..adc749c 100644
--- a/common/hw-gfx-gma-config_helpers.adb
+++ b/common/hw-gfx-gma-config_helpers.adb
@@ -30,6 +30,13 @@
    begin
       return
         (case Config.CPU is
+            when G45 =>
+               (case Port is
+                   when Internal     => LVDS,
+                   when HDMI1 | DP1  => DIGI_B,
+                   when HDMI2 | DP2  => DIGI_C,
+                   when HDMI3 | DP3  => DIGI_D,
+                   when Analog       => VGA),
             when Ironlake .. Ivybridge => -- everything but eDP through FDI/PCH
               (if Config.Internal_Is_EDP and then Port = Internal then
                   DIGI_A