drm: add register and unregister functions for connectors

Introduce generic functions to register and unregister connectors. This
provides a common place to add and remove associated user space
interfaces.

Signed-off-by: Thomas Wood <thomas.wood@intel.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 251b75e..5512c99 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -878,6 +878,8 @@
 			      struct drm_connector *connector,
 			      const struct drm_connector_funcs *funcs,
 			      int connector_type);
+int drm_connector_register(struct drm_connector *connector);
+void drm_connector_unregister(struct drm_connector *connector);
 
 extern void drm_connector_cleanup(struct drm_connector *connector);
 /* helper to unplug all connectors from sysfs for device */