OMAPDSS: DISPC: Revert to older DISPC Smart Standby mechanism for OMAP5

DISPC on OMAP5 has a more optimised mechanism of asserting Mstandby to achieve
more power savings when DISPC is configured in Smart Standby mode. This
mechanism leads to underflows when multiple DISPC pipes are enabled.

There is a register field which can let us revert to the older mechanism of
asserting Mstandby. Configure this field to prevent underflows.

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dispc.h b/drivers/video/omap2/dss/dispc.h
index 222363c6..de4863d 100644
--- a/drivers/video/omap2/dss/dispc.h
+++ b/drivers/video/omap2/dss/dispc.h
@@ -39,6 +39,7 @@
 #define DISPC_GLOBAL_BUFFER		0x0800
 #define DISPC_CONTROL3                  0x0848
 #define DISPC_CONFIG3                   0x084C
+#define DISPC_MSTANDBY_CTRL		0x0858
 
 /* DISPC overlay registers */
 #define DISPC_OVL_BA0(n)		(DISPC_OVL_BASE(n) + \