Draft: correction of ast_control_pvt_cause indication

pjsip is updating the cause_code and indicating it with AST_CONTROL_PVT_CAUSE_CODE on each incoming response.

chan_pjsip/chan_pjsip_incoming_response_update_cause{
  update cause_code with each incoming response,
  indicate AST_CONTROL_PVT_CAUSE_CODE
}

and chan-brcm doing the tone-playing and state-changing based on the indication received which includes this run-time temp cause_code. This leads to some race conditions(released during re-invite).

chan_brcm/brcm_indicate{
  AST_CONTROL_PVT_CAUSE_CODE
    tone playing/ state changing
}

As the cause_code is also used by chan_pjsip/chan_pjsip_session_end/ast_queue_hangup_with_cause, and then used for ast_channel_hangupcause_set through app_dial. We should move the part for AST_CONTROL_PVT_CAUSE_CODE from brcm_indicate to brcm_hangup by using ast_channel_hangupcause