[lld] [lld][WebAssembly] Set the target-cpu in LTO config (PR #140010)

[Sam Clegg via llvm-commits]

sbc100 wrote:

With this added how are you actually passing `-mcpu=lime1`?   i.e. are you doing something like `-mllvm,-mcpu=lime1`?  Can you mention that in the PR description?

https://github.com/llvm/llvm-project/pull/140010