Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3b2aa9a..bb18ed0 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
  *  Original Copyright (C) 1995  Linus Torvalds
- * 
- * 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.
  */
 #include <linux/cpu.h>
 #include <linux/delay.h>