[llvm] [RISCV] add load/store misched/PostRA cluster options (PR #149409)

[Mikhail Gudim via llvm-commits]

https://github.com/mgudim approved this pull request.

LGTM, but let's wait to see what others say if it is OK to remove the old options.

https://github.com/llvm/llvm-project/pull/149409