WPS: Add RF bands attribute conditionally to Probe Response frame

WSC IE in Beacon and Probe Response frames should behave consistently
as far as the RF Bands attribute is concerned. Use the same dualband
condition for adding this into Probe Response frames since the value
is not really needed if the AP is not a dualband AP.

Signed-hostap: Jouni Malinen <j@w1.fi>

src/wps/wps_registrar.c

@@ -1293,7 +1293,7 @@ static int wps_set_ie(struct wps_registrar *reg)
 	    wps_build_uuid_e(probe, reg->wps->uuid) ||
 	    wps_build_device_attrs(&reg->wps->dev, probe) ||
 	    wps_build_probe_config_methods(reg, probe) ||
-	    wps_build_rf_bands(&reg->wps->dev, probe) ||
+	    (reg->dualband && wps_build_rf_bands(&reg->wps->dev, probe)) ||
 	    wps_build_wfa_ext(probe, 0, auth_macs, count) ||
 	    wps_build_vendor_ext(&reg->wps->dev, probe)) {
 		wpabuf_free(beacon);