NTDisconnect(
  IN  tDEVICECONTEXT  *pDeviceContext,
  IN  PIRP            pIrp
  );
Routine Description:

    This Routine handles calling the Non OS specific code to disconnect a
    session.

Arguments:

    pIrp - a  ptr to an IRP

Return Value:

    NTSTATUS - status of the request