[llvm] [RISCV] Don't outline pcrel_lo when the function has a section prefix (PR #107943)

[Sam Elliott via llvm-commits]

lenary wrote:

(Part of the reason I'm saying "the right fix today" is i think this is a candidate for backporting to the release branch. I think this has probably missed 19.1.0-final, but I'd like it to be ready if there's a 19.1.1)

https://github.com/llvm/llvm-project/pull/107943