Add format string for displaying SPN in Wi-Fi calling mode.

Bug: 19681794
Change-Id: I31feab956d14accda73288cd43a2aa34db7175ae

core/res/res/values-mcc310-mnc260/strings.xml

@@ -29,4 +29,6 @@
     <string-array name="wfcOperatorErrorMessages">
         <item>Wi-Fi Calling isn\&apos;t available. Contact your carrier to enable Wi-Fi Calling.</item>
     </string-array>
+    <!-- Template for showing cellular network operator name while WFC is active -->
+    <string name="wfcSpnFormat">%s Wi-Fi Calling</string>
 </resources>

core/res/res/values/strings.xml

@@ -251,6 +251,8 @@
     <string-array name="wfcOperatorErrorCodes" translatable="false" />
     <!-- WFC Operator Error Messages -->
     <string-array name="wfcOperatorErrorMessages" />
+    <!-- Template for showing cellular network operator name while WFC is active -->
+    <string name="wfcSpnFormat">%s</string>
 
     <!--
         {0} is one of "bearerServiceCode*"

core/res/res/values/symbols.xml

@@ -748,6 +748,7 @@
   <java-symbol type="string" name="wfcRegErrorTitle" />
   <java-symbol type="array" name="wfcOperatorErrorCodes" />
   <java-symbol type="array" name="wfcOperatorErrorMessages" />
+  <java-symbol type="string" name="wfcSpnFormat" />
   <java-symbol type="string" name="policydesc_disableCamera" />
   <java-symbol type="string" name="policydesc_encryptedStorage" />
   <java-symbol type="string" name="policydesc_expirePassword" />