iwlwifi: mvm: support dqa-mode agg on non-shared queue

In non-shared queues, DQA requires re-configuring existing
queues to become aggregated rather than allocating a new
one. It also requires "un-aggregating" an existing queue
when aggregations are turned off.

Support this requirement for non-shared queues.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>