Clarify what the trunkmaxsize value is in (bytes).

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@50704 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configs/iax.conf.sample

@@ -173,7 +173,7 @@ forcejitterbuffer=no
 ; trunkmtu = 0
 ;
 
-; This option defines the maximum size an IAX2 trunk can grow to. The default value is 128000 which
+; This option defines the maximum size an IAX2 trunk can grow to. The default value is 128000 bytes which
 ; represents 40ms uncompressed linear with 200 channels. Depending on different things though
 ; (codec in use and channels) you may need to make this value larger.
 ; trunkmaxsize = 128000