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/drivers/mtd/nand/spi/Kconfig b/drivers/mtd/nand/spi/Kconfig
index 2197cb5..0777dfd 100644
--- a/drivers/mtd/nand/spi/Kconfig
+++ b/drivers/mtd/nand/spi/Kconfig
@@ -1,6 +1,6 @@
 menuconfig MTD_SPI_NAND
 	bool "SPI NAND device Support"
-	depends on MTD && DM_SPI
+	depends on DM_MTD && DM_SPI
 	select MTD_NAND_CORE
 	select SPI_MEM
 	help