[llvm] [RISCV] Add patterns for generating QC_CTO and QC_CLO (PR #144532)

[Sam Elliott via llvm-commits]

lenary wrote:

Can you add a note to the commit message saying that for pattern coverage reasons, these patterns are only added when you also have Zbb (which contains `ctz`/`clz`)

https://github.com/llvm/llvm-project/pull/144532