[v0.11.0][Perf] Eliminating the zerolike operator through patch (#3632)

### What this PR does / why we need it?
There is a zero-like operator before the attention operation in each
decoding stage. After analysis, this operator can be eliminated. The
purpose of this PR is to remove this operator and improve performance.

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Signed-off-by: ZYang6263 <zy626375@gmail.com>

vllm_ascend/torchair/torchair_attention.py

@@ -350,7 +350,7 @@ class AscendAttentionTorchairBackendImpl(AttentionImpl):
             return output.view(num_tokens, self.hidden_size)
 
         if attn_metadata is None:
-            return output.view(num_tokens, self.hidden_size)
+            return output.view(num_tokens, self.hidden_size).fill_(0)
 
         output = output.view(-1, self.num_heads, self.head_size)