[llvm] [AMDGPU] Fix maximum physical LDS reporting for gfx6 (PR #223185)

[Matt Arsenault via llvm-commits]

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@@ -276,6 +276,23 @@ TEST_F(AMDGPUTestBase, TestOccupancyAbsoluteLimits) {
                      256);
 }
 
+TEST_F(AMDGPUTestBase, TestGFX6LocalMemorySize) {
+  for (StringRef CPU : {"gfx600", "gfx601", "gfx602"}) {
+    SCOPED_TRACE(CPU.str());
+    auto TM = createAMDGPUTargetMachine(Triple("amdgcn-amd-amdhsa"), CPU, "");
----------------
arsenm wrote:

```suggestion
  for (Triple::SubArchType SubArch : {Triple::AMDGPUSubArch_600, Triple::AMDGPUSubArch_601, Triple::AMDGPUSubArch_602}) {
    SCOPED_TRACE(CPU.str());
    auto TM = createAMDGPUTargetMachine(Triple(Triple::amdgpu, SubArch), "", "");
```

Use sub arch and don't use CPU 

https://github.com/llvm/llvm-project/pull/223185