[llvm] [Exegesis][RISCV] Add RISCV support for llvm-exegesis (PR #89047)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> @dtcxzyw, do you have any objections? Could you resolve your change request?

No. Feel free to land this patch :)


https://github.com/llvm/llvm-project/pull/89047