Give SL4A access to @hide Wifi APIs

Bug: 138801922
Test: compiles
Change-Id: Icaa98f7b6d3835ab87eea9ede24fef360f52003a
diff --git a/wifi/Android.bp b/wifi/Android.bp
index 9739b2a..eda81fc 100644
--- a/wifi/Android.bp
+++ b/wifi/Android.bp
@@ -51,6 +51,7 @@
     "//frameworks/opt/net/wifi/libs/WifiTrackerLib/tests",
     "//external/robolectric-shadows:__subpackages__",
     "//frameworks/base/packages/SettingsLib/tests/integ",
+    "//external/sl4a:__subpackages__",
 ]
 
 java_library {