[PATCH] Convert users to tty_unregister_ldisc()

tty_register_ldisc(N_FOO, NULL) => tty_unregister_ldisc(N_FOO)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/net/slip.c b/drivers/net/slip.c
index 8f7841c..1911271 100644
--- a/drivers/net/slip.c
+++ b/drivers/net/slip.c
@@ -1430,7 +1430,7 @@
 	kfree(slip_devs);
 	slip_devs = NULL;
 
-	if ((i = tty_register_ldisc(N_SLIP, NULL)))
+	if ((i = tty_unregister_ldisc(N_SLIP)))
 	{
 		printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
 	}