mtd: ensure MTD is compiled when there is a SPI NOR flash using MTD

MTD must be enabled when there is a SPI NOR flash using the
SPI_FLASH_MTD config entry.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
diff --git a/configs/P1022DS_SDCARD_defconfig b/configs/P1022DS_SDCARD_defconfig
index fec645a..c384c96 100644
--- a/configs/P1022DS_SDCARD_defconfig
+++ b/configs/P1022DS_SDCARD_defconfig
@@ -44,6 +44,7 @@
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_FSL_ESDHC=y
+CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y
 CONFIG_FLASH_CFI_MTD=y