treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_147.RULE

Based on the normalized pattern:

    licensed under gplv2

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>

Documentation/arm/samsung-s3c24xx/cpufreq.rst

+.. SPDX-License-Identifier: GPL-2.0-only
 =======================
 S3C24XX CPUfreq support
 =======================
@@ -73,4 +74,3 @@ Document Author
 ---------------
 
 Ben Dooks, Copyright 2009 Simtec Electronics
-Licensed under GPLv2