Add license to ndk_headers.

Test: make ndk
Bug: None
Change-Id: I9cf8203239534831017537cb0daea11decbdf746
diff --git a/Android.bp b/Android.bp
index 59ddbdd..bf35ebf 100644
--- a/Android.bp
+++ b/Android.bp
@@ -74,6 +74,7 @@
     from: "include/nativehelper",
     to: "",
     srcs: ["include/nativehelper/jni.h"],
+    license: "NOTICE",
 }
 
 //