Fix multiple substitutions specified in non-positional format.

aapt2 is warning about not having set up a string correctly to specify the order of the substitutions.

This fixes:
[ 78% 63378/81220] AAPT2 compile out/target/common/obj/APPS/TeleService_intermediates/flat-res/packages/services/Telephony/res/values_strings.arsc.flat <- packages/services/
packages/services/Telephony/res/values/strings.xml:54: warn: multiple substitutions specified in non-positional format; did you mean to add the formatted="false" attribute?.

Change-Id: I06aa2962763ebcf5cf21fc34a0b39d70f50d2fde
Test: None
diff --git a/res/values/strings.xml b/res/values/strings.xml
index b3889dd..8fd194a 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -51,7 +51,7 @@
     <!-- Label for "cancel" button on the MMI dialog -->
     <string name="cancel">Cancel</string>
     <!-- Toast string displayed to user if the input in MMI dialog is < 1 or > 160 -->
-    <string name="enter_input">USSD message must be between <xliff:g id="min_len" >%d</xliff:g> and <xliff:g id="max_len" >%d</xliff:g> characters. Please try again.</string>
+    <string name="enter_input">USSD message must be between <xliff:g id="min_len" >%1$d</xliff:g> and <xliff:g id="max_len" >%2$d</xliff:g> characters. Please try again.</string>
 
     <!-- Label for "Manage conference call" panel [CHAR LIMIT=40] -->
     <string name="manageConferenceLabel">Manage conference call</string>