Removed unused num_concurrent_processes.

Implemented counting of queues in QPD. This makes counting the queue
list repeatedly in several places unnecessary.
Signed-off-by: NFelix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: NOded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: NOded Gabbay <oded.gabbay@gmail.com>