NXP backend: Remove max_pool2d maximum kernel size restriction.

[MartinPavella]

Summary

Neutron SW 3.1.1 removes the restriction for maximum supported kernel size of the MaxPool2D operator. This PR reflects this change in the Neutron backend.

Test plan

Unit test provided.

cc @robert-kalmar @JakeStevens @digantdesai @rascani

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/19688

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❗ 1 Active SEVs

There are 1 currently active SEVs. If your PR is affected, please view them below:

• Run pull request jobs on OSDC runners in shadow mode

❌ 1 New Failure, 2 Unrelated Failures

As of commit 04ad5fb with merge base 477707f ():

NEW FAILURE - The following job has failed:

• pull / test-llama-runner-qnn-linux (fp32, qnn_8a8w, qnn) / linux-job (gh)
  RuntimeError: Command docker exec -t 26188fff31ec047793f1037d0a909fe7aebc011dd33b966a0554f9e8d970ce44 /exec failed with exit code 1

FLAKY - The following job failed but was likely due to flakiness present on trunk:

• pull / unittest-editable / macos / macos-job (gh) (detected as infra flaky with no log or failing log classifier)

BROKEN TRUNK - The following job failed but was present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / macos / macos-job (gh) (trunk failure)
  ##[error]The operation was canceled.

This comment was automatically generated by Dr. CI and updates every 15 minutes.

[MartinPavella]

The failing checks seem unrelated and the internal CI is passing. Merging.