treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 72

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
  any later at your option 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 1 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071859.749329557@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/netfilter/xt_nfacct.c

+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
  * (C) 2011 Intra2net AG <http://www.intra2net.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 (or any
- * later at your option) as published by the Free Software Foundation.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt