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/drivers/spi/Makefile b/drivers/spi/Makefile
index 896b093..fa9a1d2 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -42,6 +42,7 @@
 obj-$(CONFIG_SANDBOX_SPI) += sandbox_spi.o
 obj-$(CONFIG_SH_SPI) += sh_spi.o
 obj-$(CONFIG_SH_QSPI) += sh_qspi.o
+obj-$(CONFIG_STM32_QSPI) += stm32_qspi.o
 obj-$(CONFIG_TEGRA114_SPI) += tegra114_spi.o
 obj-$(CONFIG_TEGRA20_SFLASH) += tegra20_sflash.o
 obj-$(CONFIG_TEGRA20_SLINK) += tegra20_slink.o