wifi: iwlwifi: mvm: set gtk id also in older FWs

We use gtk[i].id, but it is not even set in older FW APIs
(iwl_wowlan_status_v6 and iwl_wowlan_status_v7).
Set it also in older FWs.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250710212632.e91e49590414.I27d2fdbed1c54aee59929fa11ec169f07e159406@changeid