bugfix for mtp with multistream_moe (#3419)

### What this PR does / why we need it?
when infer deepseek mtp layer with multistream_moe, we should pass a
boolean to evaluate this feature and fix bugs when we are in mtp layer

- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0

---------

Signed-off-by: zouyida2052 <zouyida2002@gmail.com>

vllm_ascend/attention/utils.py

@@ -103,8 +103,6 @@ def split_decodes_and_prefills(
         return num_reqs, 0, num_tokens, 0
 
     first_prefill = is_prefill.int().argmax(dim=-1).item()
-    assert torch.all(query_lens[first_prefill:] > decode_threshold)
-    assert torch.all(query_lens[:first_prefill] <= decode_threshold)
     num_decodes = first_prefill
     num_prefills = num_reqs - num_decodes
     num_decode_tokens = query_start_loc[first_prefill].item()