net: tun.c fix cast

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index a82b32b..e6bbc63 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -900,7 +900,7 @@
 		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
 			return -EINVAL;
 		rtnl_lock();
-		ret = update_filter(&tun->txflt, (void *) __user arg);
+		ret = update_filter(&tun->txflt, (void __user *)arg);
 		rtnl_unlock();
 		return ret;