Convert CONFIG_NAND to Kconfig

This converts the following to Kconfig:
   CONFIG_NAND

Signed-off-by: Adam Ford <aford173@gmail.com>
[trini: Sync up a few more, add imply's]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/cm_t335_defconfig b/configs/cm_t335_defconfig
index 1be7b36..a1e95a1 100644
--- a/configs/cm_t335_defconfig
+++ b/configs/cm_t335_defconfig
@@ -54,6 +54,7 @@
 CONFIG_LED_STATUS_BOOT=0
 CONFIG_MMC_OMAP_HS=y
 CONFIG_PHYLIB=y
+CONFIG_NAND=y
 CONFIG_SYS_NS16550=y
 CONFIG_FAT_WRITE=y
 CONFIG_OF_LIBFDT=y