Wi-SUN border router starts faster in static configuration

If backbone is started in static mode we dont wait for the extra 4
minutes if we have been put to dynamic environment

When we dont have backbone available at all we will start the Wi-SUN
with ULA prefix after 5 minutes

source/6LoWPAN/ws/ws_bbr_api.c

@@ -665,9 +665,16 @@ static void ws_bbr_rpl_status_check(protocol_interface_info_entry_t *cur)
      */
     if ((configuration & BBR_ULA_C) == 0 && memcmp(global_prefix, ADDR_UNSPECIFIED, 8) == 0) {
         //Global prefix not available count if backup ULA should be created
+        uint32_t prefix_wait_time = BBR_BACKUP_ULA_DELAY;
         global_prefix_unavailable_timer += BBR_CHECK_INTERVAL;
-        tr_debug("Check for backup prefix %"PRIu32"", global_prefix_unavailable_timer);
-        if (global_prefix_unavailable_timer >= BBR_BACKUP_ULA_DELAY) {
+
+        if (NULL != ws_bbr_bb_static_prefix_get(NULL)) {
+            // If we have a static configuration we activate it faster.
+            prefix_wait_time = 40;
+        }
+
+        tr_debug("Check for backup prefix %"PRIu32" / %"PRIu32"", prefix_wait_time, global_prefix_unavailable_timer);
+        if (global_prefix_unavailable_timer >= prefix_wait_time) {
             if (memcmp(current_global_prefix, ADDR_UNSPECIFIED, 8) == 0) {
                 tr_info("start using backup prefix %s", trace_ipv6_prefix(local_prefix, 64));
             }