limeTRX does not check StreamCreate before adding the substream #404

stream->Add(device->StreamCreate(streamCfg, index));

StreamComposite::Add stores the raw pointer without validation. StreamCreate returns null when the board's stream port is unavailable (LimeSDR_XTRX) or when the internal TRXLooper::Setup rejects the configuration, and StreamComposite::Setup then dereferences it while summing the per-device channel counts.