OMAPDSS: DISPC: fix context restore

DISPC_MSTANDBY_CTRL register is used in the driver, but it's not
restored in dispc_restore_context(), causing problems after resume.

Instead of adding DISPC_MSTANDBY_CTRL to dispc_restore_context(), let's
call _omap_dispc_initial_config() as the first thing in
dispc_runtime_resume(). This will initialize the DISPC core registers
properly, and will avoid similar issues in the future.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/dss/dispc.c

@@ -3740,6 +3740,8 @@ static int dispc_runtime_suspend(struct device *dev)
 
 static int dispc_runtime_resume(struct device *dev)
 {
+	_omap_dispc_initial_config();
+
 	dispc_restore_context();
 
 	return 0;