i2c: stm32: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style
in header file related to STM32 Driver for I2C hardware
bus support.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used)

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46

Suggested-by: Joe Perches <[email protected]>
Signed-off-by: Nishad Kamdar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: nishadkamdar

drivers/i2c/busses/i2c-stm32.h

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * i2c-stm32.h
  *