TTY: remove tty driver re-set from tty_reopen

This is from tty_reopen:
    struct tty_driver *driver = tty->driver;
    ...
    tty->driver = driver;
and it doesn't make sense at all. The driver is intended to be set in
initialize_tty_struct from tty_init_dev (initial open). So this set in
tty_reopen is not needed.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_io.c

@@ -1348,7 +1348,6 @@ static int tty_reopen(struct tty_struct *tty)
 		tty->link->count++;
 	}
 	tty->count++;
-	tty->driver = driver; /* N.B. why do this every time?? */
 
 	mutex_lock(&tty->ldisc_mutex);
 	WARN_ON(!test_bit(TTY_LDISC, &tty->flags));