treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 466

Based on 1 normalized pattern(s):

  license__ = gpl version 2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to add the SPDX identifier to this file.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081202.640009675@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py

 #!/usr/bin/python
+# SPDX-License-Identifier: GPL-2.0-only
 # -*- coding: utf-8 -*-
 #
 """ This utility can be used to debug and tune the performance of the