[llvm] [TTI/RISCV] Strip getMaxVScale (PR #220547)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> But I think to reduce test churn we'll need to go through these tests and add `vscale_range(minVLEN / 64, 1024)` to them.

Thanks, I've tried a best-effort diff minimization.

https://github.com/llvm/llvm-project/pull/220547