Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/pwm/pwm-puv3.c b/drivers/pwm/pwm-puv3.c
index 754fd9a..9d0bd87 100644
--- a/drivers/pwm/pwm-puv3.c
+++ b/drivers/pwm/pwm-puv3.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/arch/unicore32/kernel/pwm.c
  *
@@ -5,10 +6,6 @@
  *
  *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
  *	Copyright (C) 2001-2010 Guan Xuetao
- *
- * 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/module.h>