Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/sh/kernel/irq_32.c b/arch/sh/kernel/irq_32.c
index e5a755b..e09cdc4 100644
--- a/arch/sh/kernel/irq_32.c
+++ b/arch/sh/kernel/irq_32.c
@@ -1,11 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * SHcompact irqflags support
  *
  * Copyright (C) 2006 - 2009 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/irqflags.h>
 #include <linux/module.h>