treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 224

Based on 1 normalized pattern(s):

  subject to the gnu public license v2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171440.222651153@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/lib/copy_user_64.S

+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright 2008 Vitaly Mayatskikh <vmayatsk@redhat.com>
  * Copyright 2002 Andi Kleen, SuSE Labs.
- * Subject to the GNU Public License v2.
  *
  * Functions to copy from and to user space.
  */