Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/mtd/maps/lantiq-flash.c b/drivers/mtd/maps/lantiq-flash.c
index 77b1d80..67a1dbf 100644
--- a/drivers/mtd/maps/lantiq-flash.c
+++ b/drivers/mtd/maps/lantiq-flash.c
@@ -1,7 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
- *  This program is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License version 2 as published
- *  by the Free Software Foundation.
  *
  *  Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
  *  Copyright (C) 2010 John Crispin <john@phrozen.org>