[llvm] [LegalizeVectorOps][RISCV] Use VP_FP_EXTEND/ROUND when promoting VP_FP* operations. (PR #122784)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-cmake-x86_64-avx512-win` running on `avx512-intel64-win` while building `llvm` at step 1 "checkout".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/81/builds/3613

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

```
Step 1 (checkout) failure: update (failure)
git version 2.41.0.windows.1
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': Empty reply from server
remote: Internal Server Error
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': The requested URL returned error: 500

```

</details>

https://github.com/llvm/llvm-project/pull/122784