[AMDGPU] clang-tidy: use override consistently. NFC.

Author: jayfoad

llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp

@@ -111,7 +111,7 @@ class ApplyRegBankMapping final : public GISelChangeObserver {
     B.setChangeObserver(*this);
   }
 
-  ~ApplyRegBankMapping() {
+  ~ApplyRegBankMapping() override {
     for (MachineInstr *MI : NewInsts)
       applyBank(*MI);
 

llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp

@@ -540,7 +540,7 @@ class WaitcntGeneratorPreGFX12 : public WaitcntGenerator {
     return WaitEventMaskForInstPreGFX12;
   }
 
-  virtual AMDGPU::Waitcnt getAllZeroWaitcnt(bool IncludeVSCnt) const override;
+  AMDGPU::Waitcnt getAllZeroWaitcnt(bool IncludeVSCnt) const override;
 };
 
 class WaitcntGeneratorGFX12Plus : public WaitcntGenerator {
@@ -575,7 +575,7 @@ class WaitcntGeneratorGFX12Plus : public WaitcntGenerator {
     return WaitEventMaskForInstGFX12Plus;
   }
 
-  virtual AMDGPU::Waitcnt getAllZeroWaitcnt(bool IncludeVSCnt) const override;
+  AMDGPU::Waitcnt getAllZeroWaitcnt(bool IncludeVSCnt) const override;
 };
 
 class SIInsertWaitcnts : public MachineFunctionPass {