msm_fb: Provide support for ARGC and CSC for layer mixer 2

MDP 4.4 supports additional layer mixer (LM2) with ARGC and
CSC blocks. Extend existing ARGC and CSC functionality to additional
layer mixer (LM2).

Change-Id: Id9e5d0a80fcd9a6e3b6132b083d8a43450c0efa1
Signed-off-by: Pravin Tamkhane <pravint@codeaurora.org>
diff --git a/include/linux/msm_mdp.h b/include/linux/msm_mdp.h
index 84c8bfe..a0af4b5 100644
--- a/include/linux/msm_mdp.h
+++ b/include/linux/msm_mdp.h
@@ -328,6 +328,7 @@
 	MDP_BLOCK_DMA_P,
 	MDP_BLOCK_DMA_S,
 	MDP_BLOCK_DMA_E,
+	MDP_BLOCK_OVERLAY_2,
 	MDP_BLOCK_MAX,
 };