OMAPDSS: HDMI: Move duplicate code from boardfile

Move duplicate HDMI mux_init code from omap4 and panda board file
to display file.

Signed-off-by: Mythri P K <mythripk@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/include/video/omapdss.h b/include/video/omapdss.h
index 39862b8..c1e3cb0 100644
--- a/include/video/omapdss.h
+++ b/include/video/omapdss.h
@@ -309,6 +309,8 @@
 
 /* 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(void);
 
 struct omap_display_platform_data {
 	struct omap_dss_board_info *board_data;