OMAPDSS: clean up dss_mgr_set_timings

dss_mgr_set_timings() can only be called when the output is not active.
This means that most of the code in the function is extra, as there's no
need to write the values to registers, etc, because that will be handled
when the output will be enabled.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/dss/apply.c

@@ -1314,21 +1314,19 @@ void dss_mgr_set_timings(struct omap_overlay_manager *mgr,
 		const struct omap_video_timings *timings)
 {
 	unsigned long flags;
-
-	mutex_lock(&apply_lock);
+	struct mgr_priv_data *mp = get_mgr_priv(mgr);
 
 	spin_lock_irqsave(&data_lock, flags);
 
-	dss_apply_mgr_timings(mgr, timings);
-
-	dss_write_regs();
-	dss_set_go_bits();
+	if (mp->updating) {
+		DSSERR("cannot set timings for %s: manager needs to be disabled\n",
+			mgr->name);
+		goto out;
+	}
 
+	dss_apply_mgr_timings(mgr, timings);
+out:
 	spin_unlock_irqrestore(&data_lock, flags);
-
-	wait_pending_extra_info_updates();
-
-	mutex_unlock(&apply_lock);
 }
 
 static void dss_apply_mgr_lcd_config(struct omap_overlay_manager *mgr,