Directly invoke the default phone's method in setRadioPower()

In the original implementation, SubscriptionController.getDefaultSubId()
doesn't return the correct value on boot.

b/30552536

Change-Id: Ic0a6556eaa3a1a832ba7140814ad8354b995a853
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index 9b7132b..d857087 100644
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -1403,7 +1403,14 @@
     }
 
     public boolean setRadioPower(boolean turnOn) {
-        return setRadioPowerForSubscriber(getDefaultSubscription(), turnOn);
+        final Phone defaultPhone = PhoneFactory.getDefaultPhone();
+        if (defaultPhone != null) {
+            defaultPhone.setRadioPower(turnOn);
+            return true;
+        } else {
+            loge("There's no default phone.");
+            return false;
+        }
     }
 
     public boolean setRadioPowerForSubscriber(int subId, boolean turnOn) {