[llvm] AMDGPU: Remove dead code for printing DFP immediates (PR #156644)

[Frederik Harwath via llvm-commits]

https://github.com/frederik-h requested changes to this pull request.

There is a second use of "isDFPImm" in this file. Do you want to remove that one as well while you are at it?

https://github.com/llvm/llvm-project/pull/156644