bugfix: Change module path in test_pod_kernels.py (#1842)

<!-- .github/pull_request_template.md -->

## 📌 Description

The series of code refactgor for tvm-ffi (e.g. [PR
1795](https://github.com/flashinfer-ai/flashinfer/pull/1795/files#diff-572d7ee5baecada1fd91e892d5250df6f9a90bf01e9a38c755bb6bacd2f6dd05L37))
has changed the module path of `gen_pod_module`. However, this was not
reflected in `test_pod_kernels.py`.

Current PR rectifies the import path.

Error message Before:
```
ImportError while importing test module '/flashinfer/tests/utils/test_pod_kernels.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/conda/envs/py312/lib/python3.12/importlib/__init__.py:90: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
tests/utils/test_pod_kernels.py:25: in <module>
    from flashinfer.jit.attention.pytorch import gen_pod_module
E   ModuleNotFoundError: No module named 'flashinfer.jit.attention.pytorch'
...
...
1 error in 0.20s
```


After:
```
168 passed, 24 skipped in 133.16s (0:02:13)
```
 
<!-- What does this PR do? Briefly describe the changes and why they’re
needed. -->

## 🔍 Related Issues

<!-- Link any related issues here -->

## 🚀 Pull Request Checklist

Thank you for contributing to FlashInfer! Before we review your pull
request, please make sure the following items are complete.

### ✅ Pre-commit Checks

- [x] I have installed `pre-commit` by running `pip install pre-commit`
(or used your preferred method).
- [x] I have installed the hooks with `pre-commit install`.
- [x] I have run the hooks manually with `pre-commit run --all-files`
and fixed any reported issues.

> If you are unsure about how to set up `pre-commit`, see [the
pre-commit documentation](https://pre-commit.com/).

## 🧪 Tests

- [x] Tests have been added or updated as needed.
- [x] All tests are passing (`unittest`, etc.).

## Reviewer Notes

<!-- Optional: anything you'd like reviewers to focus on, concerns, etc.
-->

Author: bkryu

tests/utils/test_pod_kernels.py

@@ -22,7 +22,7 @@
 )
 
 import flashinfer
-from flashinfer.jit.attention.pytorch import gen_pod_module
+from flashinfer.jit.attention import gen_pod_module
 
 
 @pytest.fixture(autouse=True, scope="module")