drm/connector: Warn if a connector is registered/added incorrectly

All the drivers should be converted now to use
drm_connector_dynamic_init() for MST connectors, hence
drm_connector_dynamic_register()->drm_connector_add() can WARN now if
this was not the case (for instance if a driver inited an MST connector
with one of the drm_connector_init*() functions incorrectly).

Reviewed-by: Lyude Paul <[email protected]>
Reviewed-by: Jani Nikula <[email protected]>
Acked-by: Alex Deucher <[email protected]>
Acked-by: Wayne Lin <[email protected]>
Signed-off-by: Imre Deak <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: ideak

drivers/gpu/drm/drm_connector.c

@@ -331,11 +331,7 @@ static void drm_connector_add(struct drm_connector *connector)
 	struct drm_device *dev = connector->dev;
 	struct drm_mode_config *config = &dev->mode_config;
 
-	/*
-	 * TODO: Change this to a WARN, once all drivers are converted to
-	 * call drm_connector_dynamic_init() for MST connectors.
-	 */
-	if (!list_empty(&connector->head))
+	if (drm_WARN_ON(dev, !list_empty(&connector->head)))
 		return;
 
 	spin_lock_irq(&config->connector_list_lock);