ACPI / PMIC: Replace license boilerplate with SPDX license identifier

Remove the GPL v2 license boilerplate and update with
the SPDX license identifier.
Signed-off-by: NRajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/pmic/tps68470_pmic.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * TI TPS68470 PMIC operation region driver
  *
@@ -5,15 +6,6 @@
  *
  * Author: Rajmohan Mani <rajmohan.mani@intel.com>
  *
- * 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 "as is" WITHOUT ANY WARRANTY of any
- * kind, whether express or implied; without even the implied warranty
- * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
  * Based on drivers/acpi/pmic/intel_pmic* drivers
  */