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/hikey_defconfig b/configs/hikey_defconfig
index 58eb823..15301b2 100644
--- a/configs/hikey_defconfig
+++ b/configs/hikey_defconfig
@@ -18,6 +18,7 @@
 CONFIG_ENV_FAT_DEVICE_AND_PART="1:1"
 CONFIG_MMC_DW=y
 CONFIG_MMC_DW_K3=y
+CONFIG_MTD_PARTITIONS=y
 CONFIG_CONS_INDEX=4
 CONFIG_USB=y
 CONFIG_USB_DWC2=y