Bump torch version to 2.7.1 (#1562)

### What this PR does / why we need it?
Bump torch version to 2.7.1, and cleanup infer schema patch
https://github.com/vllm-project/vllm-ascend/commit/857f489
(https://github.com/vllm-project/vllm-ascend/pull/837), this patch
depends on also: https://github.com/vllm-project/vllm-ascend/pull/1974

### Does this PR introduce any user-facing change?
No

#### How was this patch tested?
CI passed

torch-npu 2.7.1rc1 install guide:
https://gitee.com/ascend/pytorch/tree/v2.7.1/
install depending:
```
pip3 install pyyaml
pip3 install setuptools
```
install torch-npu:

Closes: https://github.com/vllm-project/vllm-ascend/issues/1866
Closes: https://github.com/vllm-project/vllm-ascend/issues/1390


- vLLM version: v0.10.0
- vLLM main:
9af654cc38

---------

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>
Signed-off-by: leo-pony <nengjunma@outlook.com>
Co-authored-by: Yikun Jiang <yikunkero@gmail.com>

README.md

@@ -42,7 +42,7 @@ By using vLLM Ascend plugin, popular open-source models, including Transformer-l
 - Software:
   * Python >= 3.9, < 3.12
   * CANN >= 8.2.rc1
-  * PyTorch >= 2.5.1, torch-npu >= 2.5.1.post1.dev20250619
+  * PyTorch >= 2.7.1, torch-npu >= 2.7.1.dev20250724
   * vLLM (the same version as vllm-ascend)
 
 ## Getting Started