stm32mp1: configs: activate CONFIG_MTD_SPI_NAND

Activate the support of SPI NAND in stm32mp1 U-Boot.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/configs/stm32mp15_basic_defconfig b/configs/stm32mp15_basic_defconfig
index 7c00eec..235c33a 100644
--- a/configs/stm32mp15_basic_defconfig
+++ b/configs/stm32mp15_basic_defconfig
@@ -88,6 +88,7 @@
 CONFIG_MTD=y
 CONFIG_NAND=y
 CONFIG_NAND_STM32_FMC2=y
+CONFIG_MTD_SPI_NAND=y
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH_MACRONIX=y
 CONFIG_SPI_FLASH_SPANSION=y