[clang] [clang] Rename files that MacOS libtool warns about (NFC) (PR #150054)

[Farzon Lotfi via cfe-commits]

================
@@ -1,4 +1,4 @@
-//===------- AMDCPU.cpp - Emit LLVM Code for builtins ---------------------===//
+//===------- BuiltinAMDCPU.cpp - Emit LLVM Code for builtins --------------===//
----------------
farzonl wrote:

```suggestion
//===------- BuiltinAMDGPU.cpp - Emit LLVM Code for builtins --------------===//
```

https://github.com/llvm/llvm-project/pull/150054