[llvm] [RISCV] Combine (mul (zext, zext)) -> (zext (mul (zext, zext))) (PR #86465)

[via llvm-commits]

github-actions[bot] wrote:

<!--LLVM CODE FORMAT COMMENT: {clang-format}-->

:white_check_mark: With the latest revision this PR passed the C/C++ code formatter.

https://github.com/llvm/llvm-project/pull/86465