ARM: SPI: stm32: add stm32f746 qspi driver

This patch adds support for the QSPI IP found in stm32f7 devices.

Signed-off-by: Michael Kurz <michi.kurz@gmail.com>
diff --git a/arch/arm/mach-stm32/stm32f7/clock.c b/arch/arm/mach-stm32/stm32f7/clock.c
index 8b3d3fd..e1ee173 100644
--- a/arch/arm/mach-stm32/stm32f7/clock.c
+++ b/arch/arm/mach-stm32/stm32f7/clock.c
@@ -266,6 +266,9 @@
 		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_RX_EN);
 		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_TX_EN);
 		break;
+	case QSPI_CLOCK_CFG:
+		setbits_le32(&STM32_RCC->ahb3enr, RCC_AHB3ENR_QSPI_EN);
+		break;
 	default:
 		break;
 	}