[llvm] `InOrderIssueStage` for llvm-mca should be generic over LSUnitBase (PR #101534)

[Chinmay Deshpande via llvm-commits]

chinmaydd wrote:

Thanks @adibiagio. I would appreciate it if someone with push privileges would help me out here. 

https://github.com/llvm/llvm-project/pull/101534