[2/4][Refactor] Refactor torchair utils (#1892)

There is a lot torchair specified logic in common code. It results hard
code maintenance. We will create a new torchair module to launch
torchair related logic there. I plan to add 4 PR.

1. Refactor worker
2. Refactor utils (this PR)
- simple change that move all torchair related util function to torchair
module
3. Refactor model_runner
4. Refactor attention

- vLLM version: v0.9.2
- vLLM main:
8188196a1c

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

vllm_ascend/torchair/torchair_worker.py

@@ -17,10 +17,10 @@ import torch
 from vllm.logger import logger
 
 import vllm_ascend.envs as envs_ascend
-from vllm_ascend.utils import (check_kv_cache_bytes_cache_exist,
-                               check_torchair_cache_exist,
-                               delete_torchair_cache_file,
-                               read_kv_cache_bytes_from_file)
+from vllm_ascend.torchair.utils import (check_kv_cache_bytes_cache_exist,
+                                        check_torchair_cache_exist,
+                                        delete_torchair_cache_file,
+                                        read_kv_cache_bytes_from_file)
 from vllm_ascend.worker.worker_v1 import NPUWorker