atomicAdd returns previous value, not current value. (microsoft#16690)

### Description
Mistake in beam scorer processing, atomicAdd result should be compared
with '1' vs '0' as it returns the original value, not the latest value.

This error just results in slow perf, nothing fails.

### Motivation and Context
Fixes microsoft#16642

Author: RyanUnderhill

onnxruntime/contrib_ops/cuda/transformers/generation_cuda_impl.cu

@@ -392,7 +392,7 @@ __global__ void BeamSearchScorer_Process(BeamScorerState& state_cpu,
     if (beam_hyp.beams_used_ == state.num_beams_) {
       if (state.early_stopping_ || !beam_hyp.CanImprove(*std::max_element(next_scores + batch_start, next_scores + batch_start + top_k), sequence_length)) {
         beam_hyp.done_ = true;
-        if (atomicAdd(&state.not_done_count_, -1) == 0)
+        if (atomicAdd(&state.not_done_count_, -1) == 1)
           state_cpu.not_done_count_ = 0;  // Update the CPU side
       }
     }