zenfone7: Add Android.bp

To avoid soong build error if if you more than 1 device tree in your source dir

Change-Id: Ib6dc42ea5a2bf0f369021393222e86eda71cfd9d
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..9515b25
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,2 @@
+soong_namespace {
+}