Convert CONFIG_MTD_PARTITIONS et al to Kconfig

This converts the following to Kconfig:
   CONFIG_MTD_PARTITIONS
   CONFIG_MTD_DEVICE

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig b/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
index e5e719d..7df6b2a 100644
--- a/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
+++ b/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
@@ -55,6 +55,7 @@
 CONFIG_MISC=y
 # CONFIG_MMC is not set
 CONFIG_DM_MMC=y
+CONFIG_MTD_DEVICE=y
 CONFIG_NAND=y
 CONFIG_NAND_ARASAN=y
 CONFIG_SPI_FLASH=y