configs: colibri_t20: enable mtd

Enable CONFIG_MTD as well to make sure UCLASS_MTD is available

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/configs/colibri_t20_defconfig b/configs/colibri_t20_defconfig
index 90777e0..e5d33ec 100644
--- a/configs/colibri_t20_defconfig
+++ b/configs/colibri_t20_defconfig
@@ -35,6 +35,7 @@
 CONFIG_SPL_DM=y
 CONFIG_DFU_MMC=y
 CONFIG_DFU_RAM=y
+CONFIG_MTD=y
 CONFIG_MTD_UBI_FASTMAP=y
 CONFIG_DM_PMIC=y
 CONFIG_DM_REGULATOR=y