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/k2g_evm_defconfig b/configs/k2g_evm_defconfig
index 2fd2dc3..0a7bb7a 100644
--- a/configs/k2g_evm_defconfig
+++ b/configs/k2g_evm_defconfig
@@ -46,6 +46,7 @@
 CONFIG_MISC=y
 CONFIG_DM_MMC=y
 CONFIG_MMC_OMAP_HS=y
+CONFIG_MTD=y
 CONFIG_MTD_RAW_NAND=y
 CONFIG_SYS_NAND_USE_FLASH_BBT=y
 CONFIG_NAND_DAVINCI=y