drm/radeon/radeon_connectors: Strip out set but unused variable 'ret'

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/radeon/radeon_connectors.c: In function ‘radeon_setup_mst_connector’:
 drivers/gpu/drm/radeon/radeon_connectors.c:2574:7: warning: variable ‘ret’ set but not used [-Wunused-but-set-variable]

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -2571,13 +2571,11 @@ void radeon_setup_mst_connector(struct drm_device *dev)
 		return;
 
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
-		int ret;
-
 		radeon_connector = to_radeon_connector(connector);
 
 		if (connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort)
 			continue;
 
-		ret = radeon_dp_mst_init(radeon_connector);
+		radeon_dp_mst_init(radeon_connector);
 	}
 }