gpio: ge: Replace GPLv2 boilerplate with SPDX

Replace the GPLv2 boilerplate text with a nice and short
SPDX header.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpio-ge.c

+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Driver for GE FPGA based GPIO
  *
  * Author: Martyn Welch <martyn.welch@ge.com>
  *
  * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
- *
- * This file is licensed under the terms of the GNU General Public License
- * version 2.  This program is licensed "as is" without any warranty of any
- * kind, whether express or implied.
  */
 
 /*