drm/radeon: add fake RN50 table for powerpc

This works well enough on a js21, but it would be nice if IBM could supply
more tables for the later Power6/7 machines.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 67358baf..95696aa 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -206,6 +206,7 @@
 	CT_MINI_INTERNAL,
 	CT_IMAC_G5_ISIGHT,
 	CT_EMAC,
+	CT_RN50_POWER,
 };
 
 enum radeon_dvo_chip {