drm/omap: omapdss.h: remove omap_hdmi_init

omap_hdmi_init() function does not exist anymore, so we can remove the
declaration.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

include/video/omapdss.h

@@ -332,8 +332,6 @@ struct omap_dss_board_info {
 
 /* Init with the board info */
 extern int omap_display_init(struct omap_dss_board_info *board_data);
-/* HDMI mux init*/
-extern int omap_hdmi_init(enum omap_hdmi_flags flags);
 
 struct omap_video_timings {
 	/* Unit: pixels */