fix API functions LMS_StartStream() and LMS_StopStream() : about limesuite HOT 1 OPEN

API_EXPORT int CALL_CONV LMS_StartStream(lms_stream_t *stream)
{
    if (stream==nullptr || stream->handle==0)
        return -1;
    return reinterpret_cast<lime::StreamChannel*>(stream->handle)->Start();
}

API_EXPORT int CALL_CONV LMS_StopStream(lms_stream_t *stream)
{
    if (stream==nullptr || stream->handle==0)
        return -1;
    return reinterpret_cast<lime::StreamChannel*>(stream->handle)->Stop();
}