hwc: Allow HWC to support Virtual Display

  This change allows virtual display to be composed
  by HWC for supporting Google WFD App + QCOM WFD stack.

Change-Id: If8892230256e72fa34e3fb5ae715c3ad8cbd5b64
diff --git a/libhwcomposer/hwc_video.h b/libhwcomposer/hwc_video.h
index 3612018..93cdaa5 100644
--- a/libhwcomposer/hwc_video.h
+++ b/libhwcomposer/hwc_video.h
@@ -45,12 +45,12 @@
     //Marks layer flags if this feature is used
     static void markFlags(hwc_layer_1_t *yuvLayer);
     //Flags if this feature is on.
-    static bool sIsModeOn[HWC_NUM_DISPLAY_TYPES];
-    static ovutils::eDest sDest[HWC_NUM_DISPLAY_TYPES];
+    static bool sIsModeOn[MAX_DISPLAYS];
+    static ovutils::eDest sDest[MAX_DISPLAYS];
 };
 
 inline void VideoOverlay::reset() {
-    for(uint32_t i = 0; i < HWC_NUM_DISPLAY_TYPES; i++) {
+    for(uint32_t i = 0; i < MAX_DISPLAYS; i++) {
         sIsModeOn[i] = false;
         sDest[i] = ovutils::OV_INVALID;
     }