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

[Krzysztof Parzyszek via cfe-commits]

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@@ -31,6 +31,15 @@ class Triple;
 // back-end to TableGen to create these clean tables.
 namespace AMDGPU {
 
+/// Address space values for AMD GPUs
+enum AddrSpace {
+  Generic = 0,
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kparzysz wrote:

We could change this enum to `enum class`.

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