drm: omapdrm: Move supported outputs feature to dss driver

The supported outputs feature is specific to the DSS, move it from the
omap_dss_features structure to the dss driver.

The omap_dss_features structure is now empty and can be removed.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/dss/dispc.c b/drivers/gpu/drm/omapdrm/dss/dispc.c
index 39a1066..4160d11 100644
--- a/drivers/gpu/drm/omapdrm/dss/dispc.c
+++ b/drivers/gpu/drm/omapdrm/dss/dispc.c
@@ -2736,7 +2736,7 @@ static int dispc_ovl_enable(enum omap_plane_id plane, bool enable)
 
 static enum omap_dss_output_id dispc_mgr_get_supported_outputs(enum omap_channel channel)
 {
-	return dss_feat_get_supported_outputs(channel);
+	return dss_get_supported_outputs(channel);
 }
 
 static void dispc_lcd_enable_signal_polarity(bool act_high)