fix lint

Signed-off-by: shen-shanshan <467638484@qq.com>

Author: shen-shanshan

vllm_ascend/worker/model_runner_v1.py

@@ -1957,6 +1957,7 @@ def execute_model(
 
             # Apply structured output bitmasks if present
             if scheduler_output.grammar_bitmask is not None:
+                assert logits is not None
                 # NOTE:
                 # 1. XGrammar bitmask applying only supports CPU and GPU.
                 # 2. The logits and bitmask should be on the same device.