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/r8a77995_draak_defconfig b/configs/r8a77995_draak_defconfig
index f451950..2897a3e 100644
--- a/configs/r8a77995_draak_defconfig
+++ b/configs/r8a77995_draak_defconfig
@@ -45,6 +45,7 @@
 CONFIG_RENESAS_SDHI=y
 CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_MTD_DEVICE=y
 CONFIG_CFI_FLASH=y
 CONFIG_RENESAS_RPC_HF=y
 CONFIG_PHY_MICREL=y