treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 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
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

at86rf230: add debugfs support

This patch introduce debugfs support for collect trac status stats. To
clear the stats ifdown the interface of at86rf230 and start the
interface again.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

ieee802154: add support for atusb transceiver

This patch adds support for the atusb transceiver.

The current driver supports basic functionality only. Possible further
tasks would be to sync functionality with the at86rf230 driver, because
the atusb use internally an at86rf231 transceiver. Some of these
features need a firmware update like AACK and ARET handling.

I did small changes to this driver to work with xmit_async callback and
setting of a random extended perm address.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Cc: Werner Almesberger <werner@almesberger.net>
Cc: Stefan Schmidt <s.schmidt@samsung.com>
Cc: Richard Sharpe <realrichardsharpe@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>