evenly: improve distribution

Was not so evenly distributed.

And it was because of the fact that cpu_cmp() was sorting descending
instead of ascending.  Which was partly covered by the fact that in
add_queue() the ci_num_queues counter was incremented *after* insert.
Because of this the insert only case was ok.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Improve add_queue() return value

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Just sort CPU LRU list, don't remove & insert again

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
evenly: add check about LRU usage

With evenly distribution difference between min and max can be only
1 CPU-wise.  Therefore add a check for this.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>