crypto: iaa - Adjust workqueue allocation type

In preparation for making the kmalloc family of allocators type aware,
we need to make sure that the returned type from the allocation matches
the type of the variable being assigned. (Before, the allocator would
always return "void *", which can be implicitly cast to any pointer type.)

The assigned type is "struct idxd_wq **", but the returned type will be
"struct wq **". These are the same size allocation (pointer sized), but
the types don't match. Adjust the allocation type to match the assignment.

Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>