iwlwifi: mvm: support new WoWLAN status FW API

iwlwifi: mvm: support new WoWLAN status FW API

A new FW API has been added for WOWLAN_GET_STATUSES to support
multiple GTK keys and IGTK keys.  Check the respective TLV and use the
new API when it is set.

Let most of the code use the new version (v7) and convert the old
version (v6) to the new one when needed.

Also refactor some functions a bit so that they can be reused more
easily.  Particularly the part that calls WOWLAN_GET_STATUSES which is
reused in D3 and D0i3.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>