Add frameworks/wilhelm to Android.bp.

Test: make native
Bug: http://b/30465923
Change-Id: I97d736deb5f1b56f0492ece4afb635539bc34610
diff --git a/root.bp b/root.bp
index 95f089b..69933e8 100644
--- a/root.bp
+++ b/root.bp
@@ -15,6 +15,7 @@
     "frameworks/av",
     "frameworks/base",
     "frameworks/native",
+    "frameworks/wilhelm",
     "hardware/*",
     "libcore",
     "libnativehelper",