NULL noise in drivers/net

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index 803a3bd..cfcd15a 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -821,7 +821,7 @@
 	tty->disc_data = NULL;
 	write_unlock(&disc_data_lock);
 
-	if (ax == 0)
+	if (!ax)
 		return;
 
 	/*