Added display initialization method

The primary display device was being configured to "blank" by
default, which prevented the boot animation from appearing
(unless you got lucky with the hardware composer state).

Bug 6975688

Change-Id: I0fa52e9e719c6e997c5725a7baf15d9718461b78
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index b1f8328..1678fe1 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -261,7 +261,7 @@
 
     if (mHwc) {
         DisplayData& disp(mDisplayData[id]);
-        if (disp.capacity < numLayers) {
+        if (disp.capacity < numLayers || disp.list == NULL) {
             const size_t size = sizeof(hwc_display_contents_1_t)
                     + numLayers * sizeof(hwc_layer_1_t);
             free(disp.list);