drm/radeon/kms: add initial radeon tv-out support.

This ports the tv-out code from the DDX to KMS.

adds a radeon.tv module option, radeon.tv=0 to disable tv

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 6c35c3c..e47f2fc 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -66,6 +66,7 @@
 extern int radeon_benchmarking;
 extern int radeon_testing;
 extern int radeon_connector_table;
+extern int radeon_tv;
 
 /*
  * Copy from radeon_drv.h so we don't have to include both and have conflicting