[llvm] [RISCV] Fix type inference ambiguity in SwapSysReg pattern (PR #184305)

[Pengcheng Wang via llvm-commits]

https://github.com/wangpc-pp commented:

I'm OK with this change, but we don't have this issue in upstream so can you explain the case where you met this problem?

https://github.com/llvm/llvm-project/pull/184305