northbridge/intel/i945/gma.c: Add and use defines for `GMADR` and `GTTADR`

Change-Id: I0f39b35fbf8e053ba21454a2847d6bb3ac5d2e1c
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/5923
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
diff --git a/src/northbridge/intel/i945/i945.h b/src/northbridge/intel/i945/i945.h
index 8212386..9be9379 100644
--- a/src/northbridge/intel/i945/i945.h
+++ b/src/northbridge/intel/i945/i945.h
@@ -87,6 +87,8 @@
 
 /* Device 0:2.0 PCI configuration space (Graphics Device) */
 
+#define GMADR		0x18
+#define GTTADR		0x1c
 #define BSM		0x5c
 #define GCFC		0xf0	/* Graphics Clock Frequency & Gating Control */