[llvm] [RISCV] Remove unnecessary patterns for tail agnostic FP intrinsics with rounding mode. (PR #94498)

[Brandon Wu via llvm-commits]

4vtomat wrote:

> > Will you also fix the vsetvli insertion pass to recognize this undef pattern?
> 
> In #93796 we were actually planning on removing LiveIntervals at O0 which will make the codegen even more sub-optimal, but hopefully in exchange for faster compilation times. So if we're committing to that then I don't think this regression matters

Thanks @lukel97 , I agree that in O0, we can exchange optimal for faster compile time~

https://github.com/llvm/llvm-project/pull/94498