android: Make valide to link wiringPi library from vendor.
diff --git a/Android.bp b/Android.bp
index c12b85c..098a4ed 100644
--- a/Android.bp
+++ b/Android.bp
@@ -49,6 +49,8 @@
         "wiringPi/wpiExtensions.c",
     ],
 
+    vendor_available: true,
+
     cflags: [
         "-UNDEBUG",
         "-DANDROID",