[llvm] [RISCV] Don't commute with shift if it would break sh{1,2,3}add pattern (PR #119527)

[Luke Lau via llvm-commits]

lukel97 wrote:

> Can you rebase on the top of #120531?

Should be rebased now, thanks for checking the codegen. 

https://github.com/llvm/llvm-project/pull/119527