Instead of using the free slots amount on the compute CQ to determine
whether we can submit work to queues, use the queues pi/ci.

This is needed in future ASICs where we don't have CQ per queue.
Signed-off-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>