[clang] [llvm] [RISCV] Add stack clash protection (PR #117612)

[Craig Topper via cfe-commits]

topperc wrote:

> @topperc thanks for the review, I followed your suggestions.

Yes. Our github configuration will only allow PRs to "squash and merge" so the separate commit won't survive.

https://github.com/llvm/llvm-project/pull/117612