Zq/impl nlloss for ascend

[NeosZhang]

Motivation and Context

tiny fix for nll_loss_v2

Description

tiny fix for nll_loss_v2

Use cases (Optional)

BC-breaking (Optional)

Checklist

Before PR:

• [ ] I have read and followed the workflow indicated in the Contributors.md to create this PR.
• [ ] Pre-commit or linting tools indicated in Contributors.md are used to fix the potential lint issues.
• [ ] Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• [ ] New functionalities are covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• [ ] The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• [ ] CLA has been signed and all committers have signed the CLA in this PR.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

:white_check_mark: jingguo-st
:x: NeosZhang

---

NeosZhang seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}