Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 3f1ef44..4bbb5f1 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -1,15 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright (C) 2014 Felix Fietkau <nbd@nbd.name>
  * Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
- *
- * 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
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #ifndef _LINUX_BITFIELD_H