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/Kconfig b/drivers/spi/Kconfig
index 0f51b3a..f3f7dbe 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -124,6 +124,14 @@
 		};
 	  };
 
+config STM32_QSPI
+	bool "STM32F7 QSPI driver"
+	depends on STM32F7
+	help
+	  Enable the STM32F7 Quad-SPI (QSPI) driver. This driver can be
+	  used to access the SPI NOR flash chips on platforms embedding
+	  this ST IP core.
+
 config TEGRA114_SPI
 	bool "nVidia Tegra114 SPI driver"
 	help