stm32mp1: add SPI flash support in SPL

Allow boot from NOR with basic boot.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/configs/stm32mp15_basic_defconfig b/configs/stm32mp15_basic_defconfig
index cc28611..adf7b61 100644
--- a/configs/stm32mp15_basic_defconfig
+++ b/configs/stm32mp15_basic_defconfig
@@ -4,6 +4,8 @@
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL=y
 CONFIG_TARGET_STM32MP1=y
+CONFIG_SPL_SPI_FLASH_SUPPORT=y
+CONFIG_SPL_SPI_SUPPORT=y
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_FIT=y
 CONFIG_BOOTCOMMAND="run bootcmd_stm32mp"
@@ -11,6 +13,7 @@
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION=3
 CONFIG_SPL_I2C_SUPPORT=y
+CONFIG_SPL_MTD_SUPPORT=y
 CONFIG_SPL_POWER_SUPPORT=y
 CONFIG_SYS_PROMPT="STM32MP> "
 # CONFIG_CMD_BOOTD is not set