Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/netrom/nr_loopback.c b/net/netrom/nr_loopback.c
index 215ad22..a880dd3 100644
--- a/net/netrom/nr_loopback.c
+++ b/net/netrom/nr_loopback.c
@@ -1,8 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
  *
  * Copyright Tomi Manninen OH2BNS (oh2bns@sral.fi)
  */
@@ -70,7 +67,7 @@
 	}
 }
 
-void __exit nr_loopback_clear(void)
+void nr_loopback_clear(void)
 {
 	del_timer_sync(&loopback_timer);
 	skb_queue_purge(&loopback_queue);