Convert CONFIG_NAND_LPC32XX_MLC to Kconfig

This converts the following to Kconfig:
   CONFIG_NAND_LPC32XX_MLC

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index bb8cffc..931257c 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -122,6 +122,11 @@
 	  Enable the driver for NAND flash on platforms using a Denali NAND
 	  controller as a DT device.
 
+config NAND_LPC32XX_MLC
+	bool "Support LPC32XX_MLC controller"
+	help
+	  Enable the LPC32XX MLC NAND controller.
+
 config NAND_LPC32XX_SLC
 	bool "Support LPC32XX_SLC controller"
 	help