[Refactor][Graph] Move graph parameter logic to acl_graph module (#3101)

### What this PR does / why we need it?
This is the follow-up PR of #2128 .

Moves graph parameter management components, including `GraphParams`,
`get_graph_params`, and `set_graph_params`, from the generic `utils.py`
to the more specific `compilation/acl_graph.py`.

Additionally, extracts the `update_attn_params` logic from the
`NPUModelRunner` class into a standalone function within the `acl_graph`
module.

This refactoring improves code organization by centralizing ACL
graph-related logic into its own dedicated module, enhancing modularity
and clarity.

### Does this PR introduce _any_ user-facing change?
None.

### How was this patch tested?
None needed.

Signed-off-by: Yizhou Liu <liu_yizhou@outlook.com>

vllm_ascend/utils.py

@@ -22,13 +22,12 @@ import functools
 import math
 import os
 from contextlib import contextmanager, nullcontext
-from dataclasses import dataclass
 from enum import Enum
 from threading import Lock
 from typing import TYPE_CHECKING, Any, List, Optional, Tuple, Union
 
 import torch
-import torch_npu  # noqa: F401  # noqa: F401
+import torch_npu  # noqa: F401
 from packaging.version import InvalidVersion, Version
 from torch_npu.npu.streams import Event
 from vllm.logger import logger
@@ -635,34 +634,3 @@ def npu_stream_switch(target_stream: torch.npu.Stream,
         return nullcontext()
     assert target_stream is not None
     return torch.npu.stream(target_stream)
-
-
-@dataclass
-class GraphParams:
-    events: dict[int, list[torch.npu.ExternalEvent]]
-    workspaces: dict[int, torch.Tensor]
-    handles: dict[int, list[torch_npu._C._NPUTaskGroupHandle]]
-    attn_params: dict[int, list[tuple]]
-
-
-_graph_params: Optional[GraphParams] = None
-
-
-def set_graph_params(aclgraph_capture_sizes: set[int]):
-    global _graph_params
-    if _graph_params is not None:
-        raise ValueError("Graph parameters have already been set!")
-    _graph_params = GraphParams(
-        {size: []
-         for size in aclgraph_capture_sizes},
-        {size: None
-         for size in aclgraph_capture_sizes},
-        {size: []
-         for size in aclgraph_capture_sizes},
-        {size: []
-         for size in aclgraph_capture_sizes},
-    )
-
-
-def get_graph_params():
-    return _graph_params