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/bk4r1_defconfig b/configs/bk4r1_defconfig
index 9b68650..7b69d68 100644
--- a/configs/bk4r1_defconfig
+++ b/configs/bk4r1_defconfig
@@ -58,7 +58,7 @@
 CONFIG_SYS_I2C_EEPROM_ADDR_LEN=2
 CONFIG_DM_MMC=y
 CONFIG_FSL_ESDHC_IMX=y
-CONFIG_MTD=y
+CONFIG_DM_MTD=y
 CONFIG_MTD_RAW_NAND=y
 CONFIG_NAND_VF610_NFC=y
 CONFIG_NAND_VF610_NFC_DT=y