surfaceflinger: clear HWC layers in Layer::onRemoved v2
am: 3851225fdd

Change-Id: Id7a9f7883a43b71737efcb645c53b4e81f8ded02
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index b43b30d..b828d6a 100755
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -296,6 +296,11 @@
     }
 
     mSurfaceFlingerConsumer->abandon();
+
+#ifdef USE_HWC2
+    clearHwcLayers();
+#endif
+
     for (const auto& child : mCurrentChildren) {
         child->onRemoved();
     }