iwlwifi: mvm: don't mark TIDs that are not idle wrt BA as inactive

A TID may not have traffic but still have a BA agreement
active (or being setup / torn down) since a BA agreement
can be triggered by a debugfs hook.
Just avoid to consider such a TID as inactive to make the
logic safer.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>