Add cortex_passes Buck target and fix quantizer dep

[JakeStevens]

Summary: Add a new cortex_passes Python library target in backends/cortex_m/passes containing the CortexMPassManager and its constituent passes (activation fusion, convert-to-cortex-m, decompose hardswish/mean, quantized clamp activation, clamp hardswish). These were previously not in any Buck target, making CortexMQuantizer unusable from Buck builds.

Differential Revision: D104841579

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/19511

• 📄 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 jobs on OSDC in pull requests shadow mode

❌ 1 New Failure, 5 Unrelated Failures

As of commit d030440 with merge base 84f39aa ():

NEW FAILURE - The following job has failed:

• pull / unittest-editable / macos / macos-job (gh)
  export/tests/test_target_recipes.py::TestTargetRecipes::test_mv2_model

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

• pull / unittest-editable / linux / linux-job (gh) (similar failure)
  exir/tests/test_joint_graph.py::TestJointGraph::test_joint_graph

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

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

• pull / unittest / linux / linux-job (gh) (trunk failure)
  exir/tests/test_joint_graph.py::TestJointGraph::test_joint_graph
• pull / unittest / macos / macos-job (gh) (trunk failure)
• pull / unittest / windows / windows-job (gh) (trunk failure)
  exir/tests/test_joint_graph.py::TestJointGraph::test_joint_graph
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)

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

[meta-codesync]

@JakeStevens has exported this pull request. If you are a Meta employee, you can view the originating Diff in D104841579.

[github-actions]

This PR needs a release notes: label

If your change should be included in the release notes (i.e. would users of this library care about this change?), please use a label starting with release notes:. This helps us keep track and include your important work in the next release notes.

To add a label, you can comment to pytorchbot, for example
@pytorchbot label "release notes: none"

For more information, see
https://github.com/pytorch/pytorch/wiki/PyTorch-AutoLabel-Bot#why-categorize-for-release-notes-and-how-does-it-work.