treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 3

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 or
  later as published by the free software foundation

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 9 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154040.848507137@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/ipv4/netfilter/nf_dup_ipv4.c

@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * (C) 2007 by Sebastian Claßen <sebastian.classen@freenet.ag>
  * (C) 2007-2010 by Jan Engelhardt <jengelh@medozas.de>
  *
  * Extracted from xt_TEE.c
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 or later, as
- * published by the Free Software Foundation.
  */
 #include <linux/ip.h>
 #include <linux/module.h>

net/ipv6/netfilter/nf_dup_ipv6.c

@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * (C) 2007 by Sebastian Claßen <sebastian.classen@freenet.ag>
  * (C) 2007-2010 by Jan Engelhardt <jengelh@medozas.de>
  *
  * Extracted from xt_TEE.c
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 or later, as
- * published by the Free Software Foundation.
  */
 #include <linux/module.h>
 #include <linux/percpu.h>

net/netfilter/xt_TEE.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	"TEE" target extension for Xtables
  *	Copyright © Sebastian Claßen, 2007
@@ -5,10 +6,6 @@
  *
  *	based on ipt_ROUTE.c from Cédric de Launois
  *	<delaunois@info.ucl.be>
- *
- *	This program is free software; you can redistribute it and/or
- *	modify it under the terms of the GNU General Public License
- *	version 2 or later, as published by the Free Software Foundation.
  */
 #include <linux/module.h>
 #include <linux/skbuff.h>