[llvm] [RISCV] Remove support for pre-RA vsetvli insertion (PR #110796)

[Luke Lau via llvm-commits]

lukel97 wrote:

> > Now that LLVM 19.1.1 has been out for a while
> 
> 
> 
> 19.1.1 was released yesterday. Maybe you meant 19.1.0?

Woops yes, will fix the PR description

https://github.com/llvm/llvm-project/pull/110796