fed advertisement fix (ARMmbed#1795)

fixed a bug where fed sent an advertisement 
when it heard a lower partition advertisement.

source/6LoWPAN/Thread/thread_router_bootstrap.c

@@ -2325,7 +2325,6 @@ static uint32_t thread_reed_timeout_calculate(thread_router_select_t *routerSele
 static int thread_reed_advertise (protocol_interface_info_entry_t *cur)
 {
  uint32_t keySequence;
- tr_debug("MLE REED ADVERTISEMENT STARTED");
  struct link_configuration *linkConfiguration;
  linkConfiguration = thread_joiner_application_get_config(cur->id);
  if (!linkConfiguration) {
@@ -2336,11 +2335,17 @@ static int thread_reed_advertise (protocol_interface_info_entry_t *cur)
  return -1;
  }
 
+ // FED not allowed to send advertisements
+ if (thread_info(cur)->thread_device_mode == THREAD_DEVICE_MODE_FULL_END_DEVICE) {
+ return -1;
+ }
+
  uint16_t bufId = mle_service_msg_allocate(cur->id, 16, false, MLE_COMMAND_ADVERTISEMENT);
  if (bufId == 0) {
  return -1;
  }
 
+ tr_debug("MLE REED ADVERTISEMENT STARTED");
  thread_management_get_current_keysequence(cur->id, &keySequence);
  mle_service_msg_update_security_params(bufId, 5, 2, keySequence);