framework-wifi: Add missing permitted package

A bug in Soong prevented the permitted package check from being
performed. Fixing the bug revealed that there was a missing package
on framework-wifi which this bug adds.

Test: m framework-wifi
Bug: 157633658
Change-Id: Ie0469de76a1bba6e9ad616a38b34e99236c7c1aa

wifi/Android.bp

@@ -120,6 +120,8 @@ java_library {
         "android.hardware.wifi",
         "android.net.wifi",
         "android.x.net.wifi",
+        // Created by jarjar rules.
+        "com.android.wifi.x",
     ],
 }