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

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

No functional change.

While here, throw away some extra blank lines.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/intel-rst.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  *  Copyright 2013 Matthew Garrett <mjg59@srcf.ucam.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.
- *
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-
 #include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -52,12 +38,10 @@ static ssize_t irst_store_wakeup_events(struct device *dev,
 	acpi = to_acpi_device(dev);
 
 	error = kstrtoul(buf, 0, &value);
-
 	if (error)
 		return error;
 
 	status = acpi_execute_simple_method(acpi->handle, "SFFS", value);
-
 	if (ACPI_FAILURE(status))
 		return -EINVAL;
 
@@ -98,12 +82,10 @@ static ssize_t irst_store_wakeup_time(struct device *dev,
 	acpi = to_acpi_device(dev);
 
 	error = kstrtoul(buf, 0, &value);
-
 	if (error)
 		return error;
 
 	status = acpi_execute_simple_method(acpi->handle, "SFTV", value);
-
 	if (ACPI_FAILURE(status))
 		return -EINVAL;