Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/c2port.h b/include/linux/c2port.h
index f273634..4e93bc6 100644
--- a/include/linux/c2port.h
+++ b/include/linux/c2port.h
@@ -1,12 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  *  Silicon Labs C2 port Linux support
  *
  *  Copyright (c) 2007 Rodolfo Giometti <giometti@linux.it>
  *  Copyright (c) 2007 Eurotech S.p.A. <info@eurotech.it>
- *
- * 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
  */
 
 #define C2PORT_NAME_LEN			32