iwlwifi: fix iwl_sta_init_lq station ID

The "is_ap" argument to iwl_sta_init_lq is never true,
so it and the corresponding code can be removed. However,
it needs to have the station ID because it is also used
for the IBSS BSSID station, and that doesn't have the
broadcast ID.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>