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/evb-rk3229_defconfig b/configs/evb-rk3229_defconfig
index 5a2466b..6b302e9 100644
--- a/configs/evb-rk3229_defconfig
+++ b/configs/evb-rk3229_defconfig
@@ -51,6 +51,7 @@
 CONFIG_SYS_I2C_ROCKCHIP=y
 CONFIG_MMC_DW=y
 CONFIG_MMC_DW_ROCKCHIP=y
+CONFIG_MTD=y
 CONFIG_DM_ETH=y
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_GMAC_ROCKCHIP=y