[llvm] [AMDGPU] Update code object metadata for kernarg preload (PR #134666)

[Matt Arsenault via llvm-commits]

================
@@ -161,14 +232,27 @@ struct AMDGPUFunctionArgInfo {
   ArgDescriptor WorkItemIDZ;
 
   // Map the index of preloaded kernel arguments to its descriptor.
-  SmallDenseMap<int, KernArgPreloadDescriptor> PreloadKernArgs{};
+  SmallDenseMap<int, KernArgPreload::KernArgPreloadDescriptor>
+      PreloadKernArgs{};
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arsenm wrote:

```suggestion
      PreloadKernArgs;
```

https://github.com/llvm/llvm-project/pull/134666