iwlwifi: mvm: support new flush API

This new API allows flushing queues based on station ID and TID in A000
devices.  One reason for using this is that tfd_queue_mask is only good
for 32 queues, which is not enough for A000 devices.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Mordechai Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>