Address comment: change pplx id type to int32

Signed-off-by: Ming Yang <yming@meta.com>

Author: minosfuture

vllm/model_executor/layers/fused_moe/pplx_prepare_finalize.py

@@ -81,7 +81,7 @@ def max_num_tokens_per_rank(self) -> Optional[int]:
         return self.max_num_tokens
 
     def topk_indices_dtype(self) -> Optional[torch.dtype]:
-        return torch.uint32
+        return torch.int32
 
     def prepare(
         self,