[llvm] [RISCV][GISel] Use relaxed_load/store in GISel atomic patterns. NFC (PR #161712)

[Craig Topper via llvm-commits]

topperc wrote:

> Sorry! Should we add a test so this won't regress?

I intend to properly support Zalasr in GISel right after this. That will contain the test. If I put a test in this patch I have to test the abort case and that seemed like more work.

https://github.com/llvm/llvm-project/pull/161712