Convert CONFIG_STM32_FLASH to Kconfig

This converts the CONFIG_STM32_FLASH to Kconfig by using
tools/moveconfig.py

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/configs/stm32f469-discovery_defconfig b/configs/stm32f469-discovery_defconfig
index 7960618..0b33e0b3 100644
--- a/configs/stm32f469-discovery_defconfig
+++ b/configs/stm32f469-discovery_defconfig
@@ -28,6 +28,7 @@
 CONFIG_MTD=y
 CONFIG_DM_MTD=y
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_STM32_FLASH=y
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH_STMICRO=y
 # CONFIG_PINCTRL_FULL is not set