add supress cng to default config for doc.

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@7791 d0543943-73ff-0310-b7d9-9358b9ac24b2

conf/sip_profiles/default.xml

@@ -75,6 +75,9 @@
     <!-- accept any authentication without actually checking (not a good feature for most people) -->
     <!-- <param name="accept-blind-auth" value="true"/> -->
     
+    <!-- supress CNG on this profile or per call with the 'supress_cng' variable -->
+    <!-- <param name="supress-cng" value="true"/> -->
+    
     <!--TTL for nonce in sip auth-->
     <param name="nonce-ttl" value="60"/>
     <!--Uncomment if you want to force the outbound leg of a bridge to only offer the codec