[llvm] [AMDGPU] Look up DefaultDepCtrEncoding instead of caching in global state (PR #227720)

[Steffen Larsen via llvm-commits]

steffenlarsen wrote:

Note that the function could also be inlined now that it's mostly just a wrapper, but I decided against it as I think it offers some readibility as-is.

https://github.com/llvm/llvm-project/pull/227720