Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/kref.h b/include/linux/kref.h
index 2922072..d32e21a 100644
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * kref.h - library routines for handling generic reference counted objects
  *
@@ -7,9 +8,6 @@
  * based on kobject.h which was:
  * Copyright (C) 2002-2003 Patrick Mochel <mochel@osdl.org>
  * Copyright (C) 2002-2003 Open Source Development Labs
- *
- * This file is released under the GPLv2.
- *
  */
 
 #ifndef _KREF_H_
@@ -53,10 +51,7 @@
  * @release: pointer to the function that will clean up the object when the
  *	     last reference to the object is released.
  *	     This pointer is required, and it is not acceptable to pass kfree
- *	     in as this function.  If the caller does pass kfree to this
- *	     function, you will be publicly mocked mercilessly by the kref
- *	     maintainer, and anyone else who happens to notice it.  You have
- *	     been warned.
+ *	     in as this function.
  *
  * Decrement the refcount, and if 0, call release().
  * Return 1 if the object was removed, otherwise return 0.  Beware, if this