[llvm] [RISCV] Remove duplicate WriteRes<WriteJalr for MIPSP8700. (PR #123865)

[Pengcheng Wang via llvm-commits]

wangpc-pp wrote:

(Actually I think the latency of jal/jalr doesn't matter at all, since they are scheduling boundaries anyway.)

https://github.com/llvm/llvm-project/pull/123865