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/qemu_arm64_defconfig b/configs/qemu_arm64_defconfig
index d2d7c38..b7c3207 100644
--- a/configs/qemu_arm64_defconfig
+++ b/configs/qemu_arm64_defconfig
@@ -21,7 +21,7 @@
 CONFIG_AHCI_PCI=y
 CONFIG_BLK=y
 # CONFIG_MMC is not set
-CONFIG_MTD=y
+CONFIG_DM_MTD=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y
 CONFIG_CFI_FLASH=y