staging: mt7621-eth: Remove license boilerplate text

Removes license boilerplate text
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-eth/ethtool.h

 /* SPDX-License-Identifier: GPL-2.0 */
-/*   This program is free software; you can redistribute it and/or modify
- *   it under the terms of the GNU General Public License as published by
- *   the Free Software Foundation; version 2 of the License
- *
- *   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.
- *
+/*
  *   Copyright (C) 2009-2016 John Crispin <blogic@openwrt.org>
  *   Copyright (C) 2009-2016 Felix Fietkau <nbd@openwrt.org>
  *   Copyright (C) 2013-2016 Michael Lee <igvtee@gmail.com>