[llvm] [RISCV] Disable use of scalable vectors for VLEN=32 (PR #185553)

[Sam Elliott via llvm-commits]

https://github.com/lenary commented:

Is this check the right way around? I'm not super familiar with V yet, so I could be wrong, but if the RealMinVLen is 32, but the RealMaxVLen is 64, we should still be able to vectorise, with a vlen=64?

https://github.com/llvm/llvm-project/pull/185553