[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-hexagon-elf` running on `hexagon-build-03` while building `llvm` at step 1 "checkout".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/40/builds/3694

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

```
Step 1 (checkout) failure: update (failure)

```

</details>

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