tty: Fix tty_port kref screwup

Pass the brown paper bags please. I changed the semantics of this so the
function was supposed to do the extra kref itself then forgot to do the
change.. duh....

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index 553b0e9..c8f8024 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -90,7 +90,7 @@
 	spin_lock_irqsave(&port->lock, flags);
 	if (port->tty)
 		tty_kref_put(port->tty);
-	port->tty = tty;
+	port->tty = tty_kref_get(tty);
 	spin_unlock_irqrestore(&port->lock, flags);
 }
 EXPORT_SYMBOL(tty_port_tty_set);