Adding HiFi5 DSP support in Cadence backend

[dijopaul]

Summary

Add support for HiFi5 DSP build in Cadence backend
Changes are in backend/cadence folder only

Test plan

Verified the build and run locally

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/21497

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❌ 1 Cancelled Job, 1 Unclassified Failure

As of commit e0158e1 with merge base 761c64c ():

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• pull / test-coreml-bc-macos (macos-m1-stable) / macos-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
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• Build Presets / zephyr (zephyr) / build (gh)

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[linux-foundation-easycla]

• ❌ - login: @dijopaul / name: Dijo Paul C. The commit (e0158e1, 01ee163, 70c70f2) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please visit our EasyCLA portal and chat with our support bot.

[dijopaul]

@pytorchbot label "release notes: none"

[mcremon-meta]

can that change break something on older toolchains? Or all of those flags are defined properly

[dijopaul]

This shouldn't break someting and its well defined in all toolchain and cores. But here we are giving -O3 by default irrespective of Debug or Release build. We thought of minimizing changes to backend cmakelist for now. If we can handle it at the topmost cmakelist it would be better.

[mcremon-meta]

@aliafzal can you take a look?

@dijopaul you need to sign the EasyCLA to get rid of the blocker, let me know if you run into any issues