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/P1020RDB-PD_SPIFLASH_defconfig b/configs/P1020RDB-PD_SPIFLASH_defconfig
index fd9be9c..c66b562 100644
--- a/configs/P1020RDB-PD_SPIFLASH_defconfig
+++ b/configs/P1020RDB-PD_SPIFLASH_defconfig
@@ -41,6 +41,7 @@
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_FSL_ESDHC=y
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_MTD_PARTITIONS=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_PHY_MARVELL=y