Add system/extras/* to the root Android.bp file

Change-Id: I15c729914392dd97e114852d43156bff1c03ed56
diff --git a/root.bp b/root.bp
index 2b72cfa..b3d1674 100644
--- a/root.bp
+++ b/root.bp
@@ -19,6 +19,7 @@
     "prebuilts/ndk",
     "prebuilts/sdk",
     "system/core/*",
+    "system/extras/*",
     "system/keymaster",
     "system/security/*",
 ]