treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 41

Based on 1 normalized pattern(s):

  this module is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 18 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170858.008906948@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/x25/x25_dev.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	X.25 Packet Layer release 002
  *
@@ -6,12 +7,6 @@
  *
  *	This code REQUIRES 2.1.15 or higher
  *
- *	This module:
- *		This module is free software; you can redistribute it and/or
- *		modify it under the terms of the GNU General Public License
- *		as published by the Free Software Foundation; either version
- *		2 of the License, or (at your option) any later version.
- *
  *	History
  *	X.25 001	Jonathan Naylor	Started coding.
  *      2000-09-04	Henner Eisen	Prevent freeing a dangling skb.