Revert "mtd: ubi: Add kconfig to handle RD at attach"

This reverts commit 47edb451.

This patch is part of the "read-disturb implementation" set of patches.
It was decided to take different approach in addressing the read disturb,
thus the whole patch series is reverted in order to simplify the code
and reduce memory footprint.

Change-Id: I598f27892f0fddf4159393b28c4446b4abf329e5
Signed-off-by: Tanya Brokhman <tlinder@codeaurora.org>