Added permission check for setCellInfoListRate

Now the caller needs to have MODIFY_PHONE_STATE to call
this API.

Test: Manual
bug: 33815946
Change-Id: Ia2cf0de383572033c70b94ae71080ef35c3f443c
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index cf86e7a..31efd0f 100644
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -752,6 +752,7 @@
     }
 
     public void setCellInfoListRate(int rateInMillis) {
+        enforceModifyPermission();
         mPhone.setCellInfoListRate(rateInMillis);
     }