[llvm] [CodeGen] MachineLICM: Do not consider "loop liveins" as loop defs (PR #121769)

[Gaëtan Bossu via llvm-commits]

gbossu wrote:

I cannot add reviewers (sad), but looking at the list of maintainers, I'd be happy to get reviews from @arsenm as general CodeGen maintainer, @TNorthover for the AArch64 changes and @asb for the RISCV changes

FYI @fhahn @sjoerdmeijer I've seen you tagged in similar PRs :)

https://github.com/llvm/llvm-project/pull/121769