[Bugfix] Fix the bug of cos invalid shape when dp (#2558)

### What this PR does / why we need it?
 Fix the bug of cos invalid shape when dp

### How was this patch tested?

- vLLM version: v0.10.1.1
- vLLM main:
1fdc732419

Signed-off-by: weiguihua2 <weiguihua2@huawei.com>

vllm_ascend/torchair/torchair_model_runner.py

@@ -419,3 +419,7 @@ class NPUTorchairModelRunner(NPUModelRunner):
 
     def _build_drafter_prepare_inputs_torchair_param(self):
         return True
+
+    def get_dp_padding(self, num_tokens):
+        """Override from NPUModelRunner to get dp padding"""
+        return 0, None