UBI: Remove alloc_ai() slab name from parameter list

There is always exactly one ubi_attach_info object allocated,
therefore we don't have to care about the name.

Signed-off-by: Richard Weinberger <richard@nod.at>
Git-commit: d2158f69a7d469c21c37f7028c18aa8c54707de3
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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