[llvm] [cmake] Set up llvm-ml as ASM_MASM tool in WinMsvc.cmake (PR #104903)

[Andrew Ng via llvm-commits]

nga888 wrote:

> Not sure - should we revert this in the meantime, until a working llvm-ml exists, or should we just keep it - as things will get fixed eventually?

Hopefully, it should be fixed now.

https://github.com/llvm/llvm-project/pull/104903