drm: Drop a redundant unused variable

Drop a redundant and unused variable "hdr_output_metadata" from
drm_connector.

Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1559159944-21103-2-git-send-email-uma.shankar@intel.com

include/drm/drm_connector.h

@@ -1244,8 +1244,6 @@ struct drm_connector {
 	 */
 	struct llist_node free_node;
 
-	/* HDR metdata */
-	struct hdr_output_metadata hdr_output_metadata;
 	struct hdr_sink_metadata hdr_sink_metadata;
 };