Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/include/asm/debugfs.h b/arch/powerpc/include/asm/debugfs.h
index 4f3b39f..2c5c485 100644
--- a/arch/powerpc/include/asm/debugfs.h
+++ b/arch/powerpc/include/asm/debugfs.h
@@ -1,13 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 #ifndef _ASM_POWERPC_DEBUGFS_H
 #define _ASM_POWERPC_DEBUGFS_H
 
 /*
  * Copyright 2017, Michael Ellerman, IBM Corporation.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
  */
 
 #include <linux/debugfs.h>