[llvm] [RISCV] Account for factor in interleave memory op costs (PR #111511)

[Luke Lau via llvm-commits]

lukel97 wrote:

> > I think we may need to either adjust the cost or add a hook to get the loop vectorizer to s
> 
> Incomplete sentence

My bad, fixed now

https://github.com/llvm/llvm-project/pull/111511