Use main looper for PhoneStateListener

Also init all subIds to INVALID in constructor

Change-Id: Ic66a2e5a24dbc10d52db0069f0e863c96ec12513
Fixes: 118070636
Test: Manual

src/com/android/settings/network/telephony/MobileDataPreferenceController.java

@@ -61,6 +61,7 @@ public class MobileDataPreferenceController extends TogglePreferenceController
         super(context, key);
         mSubscriptionManager = context.getSystemService(SubscriptionManager.class);
         mDataContentObserver = new DataContentObserver(new Handler(Looper.getMainLooper()));
+        mSubId = SubscriptionManager.INVALID_SUBSCRIPTION_ID;
     }
 
     @Override