[0.9.1][Fix] Removes explicit ATB extension registration (#1921)

### What this PR does / why we need it?
Since the ATB extension registration has now been fixed in torch_npu, we
have removed the invocation of this private method.

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

### How was this patch tested?
No need for further testing.

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

Author: yiz-liu

vllm_ascend/worker/worker_v1.py

@@ -22,7 +22,6 @@
 import torch
 import torch.nn as nn
 import torch_npu
-from torch_npu.op_plugin.atb._atb_ops import _register_atb_extensions
 from vllm import envs
 from vllm.config import VllmConfig
 from vllm.distributed import (ensure_model_parallel_initialized,
@@ -70,7 +69,6 @@ def __init__(
         # Register ops when worker init.
         from vllm_ascend import ops
         ops.register_dummy_fusion_op()
-        _register_atb_extensions()
         # init ascend config
         init_ascend_config(vllm_config)