mfd: stm32: Adopt SPDX identifier

Add SPDX identifier

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/stm32-lptimer.c b/drivers/mfd/stm32-lptimer.c
index 075330a..a00f99f 100644
--- a/drivers/mfd/stm32-lptimer.c
+++ b/drivers/mfd/stm32-lptimer.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * STM32 Low-Power Timer parent driver.
- *
  * Copyright (C) STMicroelectronics 2017
- *
  * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
- *
  * Inspired by Benjamin Gaignard's stm32-timers driver
- *
- * License terms:  GNU General Public License (GPL), version 2
  */
 
 #include <linux/mfd/stm32-lptimer.h>