[llvm] MCExpr-ify amd_kernel_code_t (PR #91587)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,24 @@
+; RUN: llc -mtriple=amdgcn-mesa-mesa3d -verify-machineinstrs < %s | FileCheck %s
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arsenm wrote:

```suggestion
; RUN: llc -mtriple=amdgcn-mesa-mesa3d < %s | FileCheck %s
```

https://github.com/llvm/llvm-project/pull/91587