### What this PR does / why we need it?
Optimize the performance of the triton operator _topk_log_softmax_kernel
in model_runner_v2 to 1.04xH100,which is 7% of its original value.(issue
https://github.com/vllm-project/vllm-ascend/issues/5208)
- vLLM version: v0.16.0
- vLLM main:
4034c3d32e
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Signed-off-by: wangx700 <wangxin700@huawei.com>