Add HWC_DISPLAY_VIRTUAL and adjust display count constants

Both surfaceflinger and HWC implementations have been defining these
themselves, making future changes more difficult. Better to define
them centrally, where they can be updated easily.

Change-Id: I793158b858c84b2470b05f9ea77cc5a0c7e247f1
diff --git a/tests/hwc/cnativewindow.c b/tests/hwc/cnativewindow.c
index 474ceec..76f4564 100644
--- a/tests/hwc/cnativewindow.c
+++ b/tests/hwc/cnativewindow.c
@@ -74,7 +74,7 @@
 	unsigned ydpi;
 	unsigned format;
 
-	hwc_display_contents_1_t *dclist[HWC_NUM_DISPLAY_TYPES];
+	hwc_display_contents_1_t *dclist[HWC_NUM_PHYSICAL_DISPLAY_TYPES];
 
 	hwc_display_contents_1_t dc;
 	hwc_layer_1_t layer[4];
@@ -200,7 +200,7 @@
 		dc->numHwLayers++;
 	}
 
-	r = hwc->prepare(hwc, HWC_NUM_DISPLAY_TYPES, win->dclist);
+	r = hwc->prepare(hwc, HWC_NUM_PHYSICAL_DISPLAY_TYPES, win->dclist);
 	if (r) {
 		ERROR("hwc->prepare failed r=%d\n",r);
 		return;
@@ -210,7 +210,7 @@
 //		LOG("dl[%d] ctype=0x%08x hints=0x%08x flags=0x%08x\n", i,
 //			dl[i].compositionType, dl[0].hints, dl[0].flags);
 
-	r = hwc->set(hwc, HWC_NUM_DISPLAY_TYPES, win->dclist);
+	r = hwc->set(hwc, HWC_NUM_PHYSICAL_DISPLAY_TYPES, win->dclist);
 	if (r) {
 		ERROR("hwc->set failed, r=%d\n", r);
 		return;