Fix WPS IE in Probe Response frame to include proper Config Methods values

This attribute is supposed to indicate which methods the AP supports as
an Enrollee for adding external Registrars. It was left to 0 when the
AP code did not yet support external Registrars and was forgotten when
the ER support was added.

src/wps/wps_registrar.c

@@ -402,7 +402,11 @@ static int wps_build_probe_config_methods(struct wps_registrar *reg,
 					  struct wpabuf *msg)
 {
 	u16 methods;
-	methods = 0;
+	/*
+	 * These are the methods that the AP supports as an Enrollee for adding
+	 * external Registrars.
+	 */
+	methods = reg->wps->config_methods & ~WPS_CONFIG_PUSHBUTTON;
 	wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
 	wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
 	wpabuf_put_be16(msg, 2);