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

[Janek van Oirschot via llvm-commits]

================
@@ -20,6 +21,7 @@ add_llvm_component_library(LLVMAMDGPUDesc
   CodeGenTypes
   Core
   MC
+  MCParser
----------------
JanekvO wrote:

Moved the `MCTargetDesc/AMDGPUMCKernelCodeT.*` files to the original `Utils/AMDKernelCodeTUtils.*` files and location. Should now adhere to the same access to parsing as prior this change.

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