hwc: User Layercache for external display

Change-Id: Ibca92e1470ef72dc02d16d4ef8c05f1a1d2d485c
diff --git a/libhwcomposer/hwc_utils.h b/libhwcomposer/hwc_utils.h
index 256b840..d7200b0 100644
--- a/libhwcomposer/hwc_utils.h
+++ b/libhwcomposer/hwc_utils.h
@@ -220,7 +220,7 @@
     qhwc::MDPInfo mMDP;
     qhwc::DisplayAttributes dpyAttr[HWC_NUM_DISPLAY_TYPES];
     qhwc::ListStats listStats[HWC_NUM_DISPLAY_TYPES];
-    qhwc::LayerCache *mLayerCache;
+    qhwc::LayerCache *mLayerCache[HWC_NUM_DISPLAY_TYPES];
     qhwc::LayerProp *layerProp[HWC_NUM_DISPLAY_TYPES];
 
     //Securing in progress indicator