[llvm] Add support for DFP IR type. (PR #69718)

[Zahira Ammarguellat via llvm-commits]

zahiraam wrote:

> Hi, Zahira. We haven't been pushing DFP changes to upstream yet. Could you submit a PR to [the dfp branch of my fork](https://github.com/tahonermann/llvm-project/tree/dfp) instead?

hmm! I thought that's what I had done!

https://github.com/llvm/llvm-project/pull/69718