libhwcomposer: Allow 2 YUV layer frames to use MDP composition

This change introduces the following changes:
- Frames having 2 yuv layer can be bypassed
- if not handled by MDP comp, video path will not
  handle any such frames and will be FB rendered

Change-Id: Id211dbc185608c482badbca00a2708fa6138a8e5
diff --git a/libhwcomposer/hwc_utils.h b/libhwcomposer/hwc_utils.h
index 5316347..9692986 100644
--- a/libhwcomposer/hwc_utils.h
+++ b/libhwcomposer/hwc_utils.h
@@ -82,7 +82,7 @@
     int fbLayerIndex; //Always last for now. = numAppLayers
     //Video specific
     int yuvCount;
-    int yuvIndex;
+    int yuvIndices[MAX_NUM_LAYERS];
     bool needsAlphaScale;
 };