Previously, the event "WPS-PBC-ACTIVE" was only generated when
wpa_supplicant is operating as WPS Registrar whereas "WPS-SUCCESS" or
"WPS-TIMEOUT" are generated for both, the Registrar and the Enrollee
roles.
Also generate the event when wpa_supplicant is operating as WPS Enrollee
to allow monitoring the begin and the end of a WPS PBC process.