treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_152.RULE

Based on the normalized pattern:

this software is distributed under the terms of the gnu general public
license ( gpl ) version 2 as published by the free software foundation
this software is provided by the copyright holders and contributors as
is and any express or implied warranties including but not limited to
the implied warranties of merchantability and fitness for a particular
purpose are disclaimed in no event shall the copyright owner or
contributors be liable for any direct indirect incidental special
exemplary or consequential damages (including but not limited to
procurement of substitute goods or services loss of use data or
profits or business interruption) however caused and on any theory of
liability whether in contract strict liability or tort (including
negligence or otherwise) arising in any way out of the use of this
software even if advised of the possibility of such damage

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>