[clang] [CIR] Upstream global variable linkage types (PR #129072)

[Andy Kaylor via cfe-commits]

================
@@ -0,0 +1,119 @@
+//===- CIROpsEnumsDialect.h - MLIR Dialect for CIR ----------------------*- C++
----------------
andykaylor wrote:

Also, the coding guidelines have changed recently, so the filename doesn't need to be in this line.
```suggestion
//===----------------------------------------------------------------------===//
```

https://github.com/llvm/llvm-project/pull/129072