since the module API is changing, it's a good time to const-ify the description() and key() return values

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@18552 65c4cc65-6c06-0410-ace0-fbb531ad65f3

formats/format_ilbc.c

@@ -163,12 +163,12 @@ int usecount()
 	return me.usecnt;
 }
 
-char *description()
+const char *description()
 {
 	return "Raw iLBC data";
 }
 
-char *key()
+const char *key()
 {
 	return ASTERISK_GPL_KEY;
 }