[llvm] [LLVM][MC][DecoderEmitter] Add support to specialize decoder per bitwidth (PR #154865)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `publish-sphinx-docs` running on `as-worker-4` while building `llvm` at step 5 "build-docs-llvm-html-docs-clang-html-docs-clang...".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/45/builds/15988

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-docs-llvm-html-docs-clang-html-docs-clang...) failure: build (failure)

```

</details>

https://github.com/llvm/llvm-project/pull/154865