[llvm] [CSKY] Don't emit `__multi3` on 32-bit CSKY (PR #69732)

[Dimitry Andric via llvm-commits]

DimitryAndric wrote:

This should be fine, but it needs a test, similar to `llvm/test/CodeGen/ARM/umulo-128-legalisation-lowering.ll`. (I don't know much about CSKY, but I assume that test case can mostly be copied except for the generated assembly code.)


https://github.com/llvm/llvm-project/pull/69732