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

[YAMAMOTO Takashi via llvm-commits]

yamt 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?

done.

i confirmed that toywasm wasm module built with https://github.com/yamt/toywasm/blob/master/build-wasm32-wasi.sh
doesn't get reference-types enabled if i did all of the following modifications.
* use wasi-sdk with https://github.com/WebAssembly/wasi-sdk/pull/527
* add -mcpu-lime1 to toywasm build
* use wasm-ld with this commit


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