tty locking fixups: remove unused "flags" variable

It became obsolete when the termios locking was changed
to use a per-tty semaphore.

drivers/char/tty_ioctl.c

@@ -394,7 +394,6 @@ int n_tty_ioctl(struct tty_struct * tty, struct file * file,
 	void __user *p = (void __user *)arg;
 	int retval;
 	struct tty_ldisc *ld;
-	unsigned long flags;
 
 	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 	    tty->driver->subtype == PTY_TYPE_MASTER)