Add LoRA linear definition

[pytorchbot]

This PR was created by the merge bot to help merge the original PR into the main branch.
ghstack PR number: #11044 by @lucylq
^ Please use this as the source of truth for the PR details, comments, and reviews
ghstack PR base: https://github.com/pytorch/executorch/tree/gh/lucylq/82/base
ghstack PR head: https://github.com/pytorch/executorch/tree/gh/lucylq/82/head
Merge bot PR base: https://github.com/pytorch/executorch/tree/main
Merge bot PR head: https://github.com/pytorch/executorch/tree/gh/lucylq/82/orig
@diff-train-skip-merge

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/12861

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❌ 2 New Failures, 2 Unrelated Failures

As of commit 172b3f5 with merge base 8da2ea6 ():

NEW FAILURES - The following jobs have failed:

• pull / unittest / linux / linux-job (gh)
  RuntimeError: Command docker exec -t bc11fec7ef93af7b985db442949638d83a4f119bac7c986d6338409d143e38b5 /exec failed with exit code 5
• pull / unittest-editable / linux / linux-job (gh)
  RuntimeError: Command docker exec -t b53a4c47008a1e2259b4d46a84372a7058b17dbfcfd44aaae2e7f0b34cfbfcd1 /exec failed with exit code 5

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

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

• pull / unittest / macos / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 5
• pull / unittest-editable / macos / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 5

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