fbdev: sh_mobile_hdmi: properly clean up modedb on monitor unplug

Even though this is not a problem currently, it is better to clear the freed
pointer and nullify the length of the freed memory.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/video/sh_mobile_hdmi.c

@@ -1071,14 +1071,17 @@ static void sh_hdmi_edid_work_fn(struct work_struct *work)
 		if (!hdmi->info)
 			goto out;
 
+		hdmi->monspec.modedb_len = 0;
+		fb_destroy_modedb(hdmi->monspec.modedb);
+		hdmi->monspec.modedb = NULL;
+
 		acquire_console_sem();
 
 		/* HDMI disconnect */
 		fb_set_suspend(hdmi->info, 1);
 
 		release_console_sem();
 		pm_runtime_put(hdmi->dev);
-		fb_destroy_modedb(hdmi->monspec.modedb);
 	}
 
 out: