[AMDGPU] Remove duplicate definition of isGFX12CacheInvOrWBInst

Author: Pierre-vh

llvm/lib/Target/AMDGPU/SIInstrInfo.h

@@ -1033,11 +1033,6 @@ class SIInstrInfo final : public AMDGPUGenInstrInfo {
            Opc == AMDGPU::GLOBAL_WBINV;
   }
 
-  static bool isGFX12CacheInvOrWBInst(unsigned Opc) {
-    return Opc == AMDGPU::GLOBAL_INV || Opc == AMDGPU::GLOBAL_WB ||
-           Opc == AMDGPU::GLOBAL_WBINV;
-  }
-
   static bool isF16PseudoScalarTrans(unsigned Opcode) {
     return Opcode == AMDGPU::V_S_EXP_F16_e64 ||
            Opcode == AMDGPU::V_S_LOG_F16_e64 ||