mtd: rename CONFIG_MTD_DEVICE -> CONFIG_MTD

Like in Linux, just use CONFIG_MTD to compile the MTD stack.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
diff --git a/configs/sam9x60ek_nandflash_defconfig b/configs/sam9x60ek_nandflash_defconfig
index 63b137d..1884bd3 100644
--- a/configs/sam9x60ek_nandflash_defconfig
+++ b/configs/sam9x60ek_nandflash_defconfig
@@ -49,6 +49,7 @@
 CONFIG_MICROCHIP_FLEXCOM=y
 CONFIG_DM_MMC=y
 CONFIG_GENERIC_ATMEL_MCI=y
+CONFIG_MTD=y
 CONFIG_MTD_RAW_NAND=y
 CONFIG_PHY_MICREL=y
 CONFIG_DM_ETH=y