[llvm] [NFC][LLVM][Mips] Cleanup pass initialization for Mips (PR #134446)

[Rahul Joshi via llvm-commits]

jurahul wrote:

Sorry, I forgot to include a link to a github issue which has the details about why we are doing this cleanup. I've added it now.

https://github.com/llvm/llvm-project/issues/111767

https://github.com/llvm/llvm-project/pull/134446