mtd: rename CONFIG_MTD -> CONFIG_DM_MTD

CONFIG_MTD must be reserved for the MTD core. Like any other
subsystem, prefix the symbol by DM when it comes to DM support.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
[trini: Add Kconfig files]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/colibri_t20_defconfig b/configs/colibri_t20_defconfig
index 0d18de0..4428433 100644
--- a/configs/colibri_t20_defconfig
+++ b/configs/colibri_t20_defconfig
@@ -42,7 +42,7 @@
 CONFIG_TFTP_BLOCKSIZE=1536
 CONFIG_SPL_DM=y
 CONFIG_SYS_I2C_TEGRA=y
-CONFIG_MTD=y
+CONFIG_DM_MTD=y
 CONFIG_MTD_UBI_FASTMAP=y
 CONFIG_DM_PMIC=y
 CONFIG_DM_REGULATOR=y