removed unused var real_tty on n_tty_ioctl()

I noted that the 'struct tty_struct *real_tty' is not used in this
function, so I removed the code about 'real_tty'.
Signed-off-by: Gustavo Fernando Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/tty_ioctl.c

@@ -981,16 +981,9 @@ EXPORT_SYMBOL_GPL(tty_perform_flush);
 int n_tty_ioctl(struct tty_struct *tty, struct file *file,
 		       unsigned int cmd, unsigned long arg)
 {
-	struct tty_struct *real_tty;
 	unsigned long flags;
 	int retval;
 
-	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
-	    tty->driver->subtype == PTY_TYPE_MASTER)
-		real_tty = tty->link;
-	else
-		real_tty = tty;
-
 	switch (cmd) {
 	case TCXONC:
 		retval = tty_check_change(tty);