[llvm] [NFC][AMDGPU] Streamline code (PR #160177)

[Jay Foad via llvm-commits]

================
@@ -6142,7 +6136,7 @@ SITargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
     // clang-format on
 
     unsigned SelOpc =
-        (WaveSize == 64) ? AMDGPU::S_CSELECT_B64 : AMDGPU::S_CSELECT_B32;
+        (ST.isWave64()) ? AMDGPU::S_CSELECT_B64 : AMDGPU::S_CSELECT_B32;
----------------
jayfoad wrote:

```suggestion
        ST.isWave64() ? AMDGPU::S_CSELECT_B64 : AMDGPU::S_CSELECT_B32;
```

https://github.com/llvm/llvm-project/pull/160177