Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/boot/treeboot-bamboo.c b/arch/powerpc/boot/treeboot-bamboo.c
index 9eee48f..97b5b16 100644
--- a/arch/powerpc/boot/treeboot-bamboo.c
+++ b/arch/powerpc/boot/treeboot-bamboo.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright IBM Corporation, 2007
  * Josh Boyer <jwboyer@linux.vnet.ibm.com>
  *
  * Based on ebony wrapper:
  * Copyright 2007 David Gibson, 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; version 2 of the License
  */
 #include "ops.h"
 #include "stdio.h"