NXP backend: Add documentation for channels last dim order support in Neutron backend + example in aot_neutron_compile.py.

[MartinPavella]

Summary

This PR adds a markdown documentation for the channels last dim order support from the NXP backend, and an example use in the aot_neutron_compile.py.

Test plan

N/A

cc @robert-kalmar

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/16223

• 📄 Preview Python docs built from this PR

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

❌ 1 New Failure, 1 Cancelled Job, 3 Unrelated Failures

As of commit 22af14b with merge base cdc2701 ():

NEW FAILURE - The following job has failed:

• pull / unittest-arm-backend-with-no-fvp (test_pytest_ops) / linux-job (gh)
  RuntimeError: Command docker exec -t 8a00cffdff1e1c4085fb07787e58afe861339899417d2790cf1b2d3382d86c3f /exec failed with exit code 1

CANCELLED JOB - The following job was cancelled. Please retry:

• pull / test-setup-linux-gcc / linux-job (gh)

BROKEN TRUNK - The following jobs failed but were present on the merge base:

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

• pull / test-binary-size-linux-gcc / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / test-openvino-linux / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.

UNSTABLE - The following job is marked as unstable, possibly due to flakiness on trunk:

• pull / android / run-emulator (gh) (#16137)
  Timeout waiting for emulator to boot.

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