mtd: ubi: Select RBTREE option from MTD_UBI Kconfig entry

Expose the RBTREE feature through Kconfig and select this option from the
MTD_UBI option.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Jagan Teki <jagan@openedev.com>
[Rebased on master]
Signed-off-by: Jagan Teki <jagan@openedev.com>
2 files changed