[Performance] Improve MiMo-Audio tokenizer decoding performance (#2183)

Signed-off-by: 齐保元 <qibaoyuan@xiaomi.com>
Co-authored-by: Jialong Liu <88185941+Galleons2029@users.noreply.github.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

vllm_omni/model_executor/models/mimo_audio/quantization.py

@@ -356,11 +356,14 @@ class ResidualVectorQuantization(nn.Module):
         return out_indices
 
     def decode(self, q_indices: torch.Tensor, st: int = 0) -> torch.Tensor:
-        quantized_out = torch.tensor(0.0, device=q_indices.device)
+        quantized_out = None
         for i, indices in enumerate(q_indices):
             layer = self.layers[st + i]
             quantized = layer.decode(indices)
-            quantized_out = quantized_out + quantized
+            if quantized_out is None:
+                quantized_out = quantized
+            else:
+                quantized_out = quantized_out + quantized
         return quantized_out