tty: char: mxser, remove unnecessary tty test

Stanse found unnecessary test in mxser_startup.

tty is dereferenced earlier, the test is superfluous. Remove it.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>