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/T2081QDS_defconfig b/configs/T2081QDS_defconfig
index ab39f2f..8e03b7c 100644
--- a/configs/T2081QDS_defconfig
+++ b/configs/T2081QDS_defconfig
@@ -28,6 +28,7 @@
 CONFIG_FSL_CAAM=y
 CONFIG_FSL_ESDHC=y
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_MTD_PARTITIONS=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_EON=y
 CONFIG_SPI_FLASH_STMICRO=y