treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_179.RULE

Based on the normalized pattern:

    gpl header start  do not alter or remove copyright notices or this
    file header  this program is free software you can redistribute it
    and/or modify it under the terms of the gnu general public license
    version 2 only as published by the free software foundation  this
    program is distributed in the hope that it will be useful but without
    any warranty without even the implied warranty of merchantability or
    fitness for a particular purpose see the gnu general public license
    version 2 for more details (a copy is included in the license file
    that accompanied this code)  you should have received a copy of the
    gnu general public license version 2 along with this program if not
    see http://www gnu org/licenses  please visit http://www

 xyratex
    com/contact if you need additional information or have any questions
    gpl header end

extracted by the scancode license scanner the SPDX license identifier

    GPL-2.0-only

has been chosen to replace the boilerplate/reference.

Reviewed-by: Allison Randal <allison@lohutok.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>