ci: enable gfx90c for PyTorch release/2.12, disable nightly

[harkgill-amd]

Motivation

Addresses #6805.

Technical Details

• Shifting gfx90c builds to release/2.12 only as gfx90c support has been backported there with [release/2.12] Update composable_kernel submodule with gfx90c support pytorch#3480
• nightly is currently blocked until CK submodule is bumped to include gfx90c support. Disabled for the time being.

Test Plan

• Trigger TheRock Multi-Arch PyTorch build w/fix branch

Test Result

• release/2.12 now builds successfully https://github.com/ROCm/TheRock/actions/runs/30103245986

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/TheRock/blob/main/CONTRIBUTING.md.

[therock-pr-bot]

❌ PR Check — Action Required

Check	Status	Details
📝 PR Title/Description	✅ Pass	—
⛔ Forbidden Files	✅ Pass	—
🧪 Unit Test	❌ Fail	Error: Source/code files changed without an accompanying unit test. Expected: add at least one test file named like test_<name>.py / test_<name>.cpp (or <name>_test.*). Current: code file(s) changed: build_tools/github_actions/configure_pytorch_release_matrix.py; no test file found
🔎 pre-commit	✅ Pass	—
🚫 Draft PR	🔜 To Be Enabled	—
🚩 Feature Flag	🔜 To Be Enabled	—
📊 Code Coverage	🔜 To Be Enabled	—

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[therock-pr-bot]

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