drm/r500: add support for AGP based cards.

AGP registers weren't programmed properly for r500 cards.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/char/drm/radeon_drv.h b/drivers/char/drm/radeon_drv.h
index d0dc47c..f43e1f9 100644
--- a/drivers/char/drm/radeon_drv.h
+++ b/drivers/char/drm/radeon_drv.h
@@ -522,9 +522,13 @@
 
 #define RV515_MC_FB_LOCATION 0x01
 #define RV515_MC_AGP_LOCATION 0x02
+#define RV515_MC_AGP_BASE     0x03
+#define RV515_MC_AGP_BASE_2   0x04
 
 #define R520_MC_FB_LOCATION 0x04
 #define R520_MC_AGP_LOCATION 0x05
+#define R520_MC_AGP_BASE     0x06
+#define R520_MC_AGP_BASE_2   0x07
 
 #define RADEON_MPP_TB_CONFIG		0x01c0
 #define RADEON_MEM_CNTL			0x0140