stm32: fix STMicroelectronics copyright

Uniformize STMicroelectronics copyrights headers for STM32
related code.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/drivers/serial/serial_stm32x7.c b/drivers/serial/serial_stm32x7.c
index a5d529c..d1580e3 100644
--- a/drivers/serial/serial_stm32x7.c
+++ b/drivers/serial/serial_stm32x7.c
@@ -1,6 +1,6 @@
 /*
- * (C) Copyright 2016
- * Vikas Manocha, <vikas.manocha@st.com>
+ * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
+ * Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */