message: fix a crash when the some IIO stacks are not active
diff: @@ -1035,7 +1035,7 @@ result_content get_IIO_Samples(PCM *m, const std::vector<struct iio_stacks_on_so
  uint64 rawEvents[4] = {0};
  std::unique_ptr<ccr> pccr(get_ccr(m, ctr.ccr));
  rawEvents[ctr.idx] = pccr->get_ccr_value();
  - int stacks_count = (int)iios[0].stacks.size();
  + const int stacks_count = (int)m->getMaxNumOfIIOStacks();
  before = new IIOCounterState[iios.size() * stacks_count];
  after = new IIOCounterState[iios.size() * stacks_count];
  