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/socfpga_arria5_defconfig b/configs/socfpga_arria5_defconfig
index a3f3d53..d6788b7 100644
--- a/configs/socfpga_arria5_defconfig
+++ b/configs/socfpga_arria5_defconfig
@@ -44,7 +44,7 @@
 CONFIG_SYS_I2C_DW=y
 CONFIG_DM_MMC=y
 CONFIG_MMC_DW=y
-CONFIG_MTD_DEVICE=y
+CONFIG_MTD=y
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_SPI_FLASH_STMICRO=y
 # CONFIG_SPI_FLASH_USE_4K_SECTORS is not set