UBI: Fix memory leak in ubi_attach_fastmap() error path

On error we have to free all three temporary lists.

Change-Id: I5667f3eb55be47bd0fcedf374f86021900743ecd
Reported-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Git-commit: fe24c6e5f51ec5ea42d432f67618a084047a23ed
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>