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/10m50_defconfig b/configs/10m50_defconfig
index e99e975..fe96d6f 100644
--- a/configs/10m50_defconfig
+++ b/configs/10m50_defconfig
@@ -26,9 +26,9 @@
 CONFIG_ALTERA_PIO=y
 CONFIG_MISC=y
 CONFIG_ALTERA_SYSID=y
+CONFIG_MTD=y
 CONFIG_DM_MTD=y
 CONFIG_MTD_NOR_FLASH=y
-CONFIG_MTD_DEVICE=y
 CONFIG_ALTERA_QSPI=y
 CONFIG_PHY_MARVELL=y
 CONFIG_DM_ETH=y