drm/atomic-helpers: Remove outdated comment

We forgot to clean this up when adding connector refcounting.

Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-10-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_atomic_helper.c

@@ -3286,11 +3286,6 @@ EXPORT_SYMBOL(drm_atomic_helper_duplicate_state);
 void
 __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
 {
-	/*
-	 * This is currently a placeholder so that drivers that subclass the
-	 * state will automatically do the right thing if code is ever added
-	 * to this function.
-	 */
 	if (state->crtc)
 		drm_connector_unreference(state->connector);
 }