[llvm] [RISCV] Add tune info for mem* expansion (PR #118439)

[Pengcheng Wang via llvm-commits]

wangpc-pp wrote:

> What's your plan for the getters in TargetLowering for the same properties? These are queried elsewhere in the codebase.

I don't get what you mean, these getters should return the same values that we set in XXXTargetLowering?

https://github.com/llvm/llvm-project/pull/118439