[llvm] [RISCV][NFC] Simplify RISCVInstrInfo::copyPhysReg (PR #84139)

[Wang Pengcheng via llvm-commits]

wangpc-pp wrote:

> Why is this not just a loop over an array of triples? Macros should be avoided in C++ where possible, and they’re not needed here.

So what need I revise them to use a loop? I think we have a lot of macros even in target-independent code.

https://github.com/llvm/llvm-project/pull/84139