Fix NNPACK header file position error

[yjcn]

Description

NNPACK header files's position has changed,So the code also need to be updated.

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [MXNET-$JIRA_ID], where $JIRA_ID refers to the relevant JIRA issue created (except PRs with tiny changes)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage:
• Unit tests are added for small changes to verify correctness (e.g. adding a new operator)
• Nightly tests are added for complicated/long-running ones (e.g. changing distributed kvstore)
• Build tests will be added for build configuration changes (e.g. adding a new build option with NCCL)
• Code is well-documented:
• For user-facing API changes, API doc string has been updated.
• For new C++ functions in header files, their functionalities and arguments are documented.
• For new examples, README.md is added to explain the what the example does, the source of the dataset, expected performance on test set and reference to the original paper if applicable
• Check the API doc at http://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-$PR_ID/$BUILD_ID/index.html
• To the my best knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

Changes

• Feature1, tests, (and when applicable, API doc)
• Feature2, tests, (and when applicable, API doc)

Comments

• If this change is a backward incompatible change, why must this change be made.
• Interesting edge cases to note here

[marcoabreu]

Am I missing something or how was it possible that it passed compilation?

[piiswrong]

I think nnpack should be moved into nn instead.

@marcoabreu nnpack is not tested in the CI. It was added a long time ago and I don't think it was officially supported

[marcoabreu]

Should we enable it?

[piiswrong]

It's likely not working properly. I think there was an issue on updating nnpack support to include latest changes from nnpack upstream. We should do that first.

[marcoabreu]

Would you mind taking care of that?

[piiswrong]

It's a major work item. We'll need to plan it

[dabraude]

I haven't had much spare time to work on it, but I have been looking into it
on PR #9860

[piiswrong]

in any case i'll merge this first since it doesn't do any harm