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/spear310_defconfig b/configs/spear310_defconfig
index e210ea7..865de76 100644
--- a/configs/spear310_defconfig
+++ b/configs/spear310_defconfig
@@ -25,8 +25,8 @@
 CONFIG_ENV_ADDR=0xF8040000
 CONFIG_SYS_I2C_DW=y
 # CONFIG_MMC is not set
+CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
-CONFIG_MTD_DEVICE=y
 CONFIG_PHY_GIGE=y
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_MII=y