[llvm] [AMDGPU][SIInsertWaitcnts][NFC] Drop MaxCounter member variable (PR #181092)

[via llvm-commits]

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@@ -354,18 +360,19 @@ class WaitcntGenerator {
   const GCNSubtarget &ST;
   const SIInstrInfo &TII;
   AMDGPU::IsaVersion IV;
-  InstCounterType MaxCounter;
+  // TODO: Shouldn't this be a reference, because IsExpertMode can change per MF
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vporpo wrote:

Yeah let me create a separate PR to fix this.

https://github.com/llvm/llvm-project/pull/181092