[llvm] [flang] [clang] [NFC][AMDGPU] Move address space enum to LLVM directory (PR #73944)

[Sam Elliott via llvm-commits]

lenary wrote:

The reason TargetParser exists is because Target directories are only added to the include path if you enable that target, but some cross-project target code needs to always be available, such as the code for Triples, even when the relevant targets are disabled. I think these address space constants have the same needs, so this location makes sense to me, but I could be wrong.

It is strange that the AMDGPU stuff is in the file called TargetParser.h, but that's because I wasn't able to move that code around when I originally split out TargetParser. Now might be a good time to put it in its own header, like was done for all other targets. 



https://github.com/llvm/llvm-project/pull/73944