[llvm] [AMDGPU] MCExpr-ify MC layer kernel descriptor (PR #80855)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,68 @@
+// RUN: llvm-mc -triple amdgcn-amd-amdhsa -mcpu=gfx90a < %s | FileCheck --check-prefix=ASM %s
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arsenm wrote:

Also needs to test more subtargets to hit all the streamer paths 

https://github.com/llvm/llvm-project/pull/80855