ethernet: dwmac-stm32: Fix copyright

Uniformize STMicroelectronics copyrights header
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
CC: Alexandre Torgue <alexandre.torgue@st.com>
Acked-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c

 /*
  * dwmac-stm32.c - DWMAC Specific Glue layer for STM32 MCU
  *
- * Copyright (C) Alexandre Torgue 2015
- * Author:  Alexandre Torgue <alexandre.torgue@gmail.com>
+ * Copyright (C) STMicroelectronics SA 2017
+ * Author:  Alexandre Torgue <alexandre.torgue@st.com> for STMicroelectronics.
  * License terms:  GNU General Public License (GPL), version 2
  *
  */