Support packets in flight

Support packets in flight

The handle_esp_bulk function might enqueue packets on a QAT device.
These packets are not necessarily dequeued in the same call to the
handle_bulk function since they might be asynchronously processed.
Therefore, in some cases, we need to call this handle_bulk
function again later, even when no new packets are received on the rx
queue. To achieve this, the TASK_FEATURE_ZERO_RX flag is set.
The number of packets in flight are stored to decide if packets need
to be dequeued or not.
The handle_esp_bulk function will continue to dequeue packets till
none are left, even in case no new packets arrive.

Signed-off-by: Luc Provoost <luc.provoost@gmail.com>
Change-Id: I15e5b92c2413a1d3823557f70b1f437b35ca5a12