component/bt: Optimized broadcast callback function, send the callback function to...

component/bt: Optimized broadcast callback function, send the callback function to the application after the controller confirms receipt of the broadcast start.

1. optimiz the ble stop adv callback function.
2. added the osi_mutex_unlock in the bta_gattc_wait4_service_change_ccc_cback function when the p_timer_param == NULL ||  p_conn == NULL.