[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.

---------

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

vllm_ascend/attention/sfa_v1.py

@@ -808,7 +808,7 @@ class AscendSFAImpl(MLAAttentionImpl):
         assert output is not None, "Output tensor must be provided."
         if attn_metadata is None:
             # Profiling run.
-            return output
+            return output.fill_(0)
         num_actual_tokens = attn_metadata.num_actual_tokens
         assert attn_metadata.num_decodes is not None and \
         attn_metadata.num_prefills is not None and \