platform/x86: intel-hid: Convert to use SPDX identifier

Reduce size of duplicated comments by switching to use SPDX identifier.

No functional change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/intel-hid.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  *  Intel HID event & 5 button array driver
  *
  *  Copyright (C) 2015 Alex Hung <alex.hung@canonical.com>
  *  Copyright (C) 2015 Andrew Lutomirski <luto@kernel.org>
- *
- *  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; either version 2 of the License, or
- *  (at your option) any later version.
- *
- *  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.
- *
  */
 
 #include <linux/acpi.h>