disp: msm: sde: update RM to support dedicated CWB

Add dummy layer mixer blocks to be used for dedicated
CWB.

Change-Id: Ie1fe4fa7502cf5cf4dba3f2c129257887a20b7ad
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>

msm/sde/sde_hw_mdss.h

@@ -153,6 +153,8 @@ enum sde_lm {
 	LM_3,
 	LM_4,
 	LM_5,
+	LM_DCWB_DUMMY_0,
+	LM_DCWB_DUMMY_1,
 	LM_6,
 	LM_MAX
 };