[llvm] [LLVM] Update Sparc maintainer (PR #120430)

[via llvm-commits]

https://github.com/koachan approved this pull request.

Thanks for the nomination! I'll be glad to accept it but first, a question:

In the link given it is said that I am expected to "engaging in their responsibilities the majority of the days in a month", but due to life circumstances I can only do larger activites (like reviews or code contributions) in a couple times every month (but I should be able to respond to messages and questions in any day just fine). Would that still be fine?

https://github.com/llvm/llvm-project/pull/120430