disp: msm: sde: add new support for digital dimming

Add new properties to support dynamically turning on and off digital
dimming and setting new minimum backlight.

Change-Id: I3b94190877d556768ba2c92ec59432dec44de0de
Signed-off-by: Ping Li <pingli@codeaurora.org>

msm/msm_drv.h

@@ -216,6 +216,8 @@ enum msm_mdp_conn_property {
 	CONNECTOR_PROP_SV_BL_SCALE,
 	CONNECTOR_PROP_SUPPORTED_COLORSPACES,
 	CONNECTOR_PROP_DYN_BIT_CLK,
+	CONNECTOR_PROP_DIMMING_CTRL,
+	CONNECTOR_PROP_DIMMING_MIN_BL,
 
 	/* enum/bitmask properties */
 	CONNECTOR_PROP_TOPOLOGY_NAME,