message: Remove the stale TODO.
  The 5-inputs LSTM was an old implementation and
  we're not actively using this in TFLite now.
diff: @@ -2369,8 +2369,6 @@ TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
  return kTfLiteError;
  }
  - // TODO(ycling): Investigate if this copy can be avoided with the 5-inputs
  - // LSTM kernel.
  memcpy(prev_activation->data.raw, activation_out->data.raw,
  activation_out->bytes);
  memcpy(prev_state->data.raw, state_out->data.raw, state_out->bytes);
  