treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 460

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 as
  published by the free software foundation http www opensource org
  licenses gpl license html http www gnu org copyleft gpl html

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 3 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081201.897982733@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>