Use the new isNetworkSupported api for wifi-only

Didn't have an API for this before so people used a hacked system property (ro.carrier)
to determine if the device supported mobile data.  Added new API and switching callsites.

bug:5087537
Change-Id: Ibd799559be102a9e2fd552d1a23d1afbcf8f4614

src/com/android/settings/fuelgauge/PowerUsageSummary.java

@@ -713,7 +713,7 @@ public class PowerUsageSummary extends PreferenceFragment implements Runnable {
         addBluetoothUsage(uSecNow);
         addIdleUsage(uSecNow); // Not including cellular idle power
         // Don't compute radio usage if it's a wifi-only device
-        if (!com.android.settings.Utils.isWifiOnly()) {
+        if (!com.android.settings.Utils.isWifiOnly(getActivity())) {
             addRadioUsage(uSecNow);
         }
     }