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/vct_premium_onenand_small_defconfig b/configs/vct_premium_onenand_small_defconfig
index ff5e7a6..64f6dfb 100644
--- a/configs/vct_premium_onenand_small_defconfig
+++ b/configs/vct_premium_onenand_small_defconfig
@@ -19,4 +19,5 @@
 # CONFIG_CMD_NET is not set
 # CONFIG_CMD_NFS is not set
 # CONFIG_CMD_MISC is not set
+CONFIG_CMD_UBI=y
 CONFIG_SYS_NS16550=y