Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/sh/kernel/io.c b/arch/sh/kernel/io.c
index 5c51b79..da22f3b 100644
--- a/arch/sh/kernel/io.c
+++ b/arch/sh/kernel/io.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * arch/sh/kernel/io.c - Machine independent I/O functions.
  *
  * Copyright (C) 2000 - 2009  Stuart Menefy
  * Copyright (C) 2005  Paul Mundt
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
  */
 #include <linux/module.h>
 #include <linux/pci.h>