[llvm] [mlir] MathExtras: avoid unnecessarily widening types (PR #95426)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> High level question: Do we need the "common type" logic? Would it be enough to require the types to be the same? Or would this introduce a lot of type casts at use-sites?

Yes, it's necessary. Otherwise, it would introduce a lot of type casts at callers.

https://github.com/llvm/llvm-project/pull/95426