Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/boot/bamboo.c b/arch/powerpc/boot/bamboo.c
index b82cacb..dcdfa58 100644
--- a/arch/powerpc/boot/bamboo.c
+++ b/arch/powerpc/boot/bamboo.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright IBM Corporation, 2007
  * Josh Boyer <jwboyer@linux.vnet.ibm.com>
@@ -7,10 +8,6 @@
  *
  * Clocking code based on code by:
  * Stefan Roese <sr@denx.de>
- *
- * 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 <stdarg.h>
 #include <stddef.h>