UBI: Fastmap: Introduce ubi_fastmap_init()

...and kill another #ifdef in wl.c. :-)

Signed-off-by: Richard Weinberger <richard@nod.at>
Git-commit: acfda79f8808518b0235eb9a13c8b5f762e43a75
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>