[main] remove dbo code (#3712)

### What this PR does / why we need it?
Remove codes of dbo.
Currently, vLLM has supported dbo with pr:
https://github.com/vllm-project/vllm/pull/23693.

### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

- vLLM version: v0.11.0rc3
- vLLM main:
17c540a993

Signed-off-by: zzzzwwjj <1183291235@qq.com>

vllm_ascend/torchair/torchair_attention.py

@@ -264,8 +264,7 @@ class AscendAttentionTorchairMetadataBuilder(AscendAttentionMetadataBuilder):
             max_query_len=common_attn_metadata.max_query_len,
             slot_mapping=slot_mapping,
             attn_mask=attn_mask,
-            attn_state=attn_state,
-            enable_dbo_across_dp=common_attn_metadata.enable_dbo_across_dp)
+            attn_state=attn_state)
         return attn_metadata