drm/connector: Check for destroy implementation

Connectors need to be cleaned up with a call to drm_connector_cleanup()
in their drm_connector_funcs.destroy implementation.

Let's check for this and complain if there's no such function.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-9-maxime@cerno.tech

drivers/gpu/drm/drm_connector.c

@@ -348,6 +348,9 @@ int drm_connector_init(struct drm_device *dev,
 		       const struct drm_connector_funcs *funcs,
 		       int connector_type)
 {
+	if (drm_WARN_ON(dev, !(funcs && funcs->destroy)))
+		return -EINVAL;
+
 	return __drm_connector_init(dev, connector, funcs, connector_type, NULL);
 }
 EXPORT_SYMBOL(drm_connector_init);
@@ -378,6 +381,9 @@ int drm_connector_init_with_ddc(struct drm_device *dev,
 				int connector_type,
 				struct i2c_adapter *ddc)
 {
+	if (drm_WARN_ON(dev, !(funcs && funcs->destroy)))
+		return -EINVAL;
+
 	return __drm_connector_init(dev, connector, funcs, connector_type, ddc);
 }
 EXPORT_SYMBOL(drm_connector_init_with_ddc);