[PATCH] mxser: remove useless fields

the session and pgrp fields in mxser_struct are unused.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>