kconfig: introduce kconfig for UBI

move the UBI config options into Kconfig.

Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Andrew F. Davis <afd@ti.com>
Reviewed by: Evgeni Dobrev <evgeni at studio-punkt.com>
diff --git a/configs/x600_defconfig b/configs/x600_defconfig
index 69501b4..47579a5 100644
--- a/configs/x600_defconfig
+++ b/configs/x600_defconfig
@@ -23,6 +23,7 @@
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
+CONFIG_CMD_UBI=y
 CONFIG_SYS_I2C_DW=y
 CONFIG_NETDEVICES=y
 CONFIG_ETH_DESIGNWARE=y