iwlwifi: mvm: iwl_mvm_wowlan_config_key_params is for wowlan only

Now that d0i3 is dead, this function can't be called from d0i3
flows. Change its signature and make it static.

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