net: stm32: add designware mac glue code for stm32

This patch adds glue code required for enabling the designware
mac on stm32f7 devices.

Signed-off-by: Michael Kurz <michi.kurz@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/arch/arm/mach-stm32/stm32f7/clock.c b/arch/arm/mach-stm32/stm32f7/clock.c
index 4faf174..8b3d3fd 100644
--- a/arch/arm/mach-stm32/stm32f7/clock.c
+++ b/arch/arm/mach-stm32/stm32f7/clock.c
@@ -261,6 +261,11 @@
 	case FMC_CLOCK_CFG:
 		setbits_le32(&STM32_RCC->ahb3enr, RCC_AHB3ENR_FMC_EN);
 		break;
+	case STMMAC_CLOCK_CFG:
+		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_EN);
+		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_RX_EN);
+		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_TX_EN);
+		break;
 	default:
 		break;
 	}