[AMDGPU] Inherit constructors from WaitcntGenerator. NFC.

Author: jayfoad

llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp

@@ -345,9 +345,7 @@ class WaitcntGenerator {
 
 class WaitcntGeneratorPreGFX12 : public WaitcntGenerator {
 public:
-  WaitcntGeneratorPreGFX12() = default;
-  WaitcntGeneratorPreGFX12(const MachineFunction &MF)
-      : WaitcntGenerator(MF, NUM_NORMAL_INST_CNTS) {}
+  using WaitcntGenerator::WaitcntGenerator;
 
   bool
   applyPreexistingWaitcnt(WaitcntBrackets &ScoreBrackets,
@@ -381,10 +379,7 @@ class WaitcntGeneratorPreGFX12 : public WaitcntGenerator {
 
 class WaitcntGeneratorGFX12Plus : public WaitcntGenerator {
 public:
-  WaitcntGeneratorGFX12Plus() = default;
-  WaitcntGeneratorGFX12Plus(const MachineFunction &MF,
-                            InstCounterType MaxCounter)
-      : WaitcntGenerator(MF, MaxCounter) {}
+  using WaitcntGenerator::WaitcntGenerator;
 
   bool
   applyPreexistingWaitcnt(WaitcntBrackets &ScoreBrackets,
@@ -2747,7 +2742,7 @@ bool SIInsertWaitcnts::run(MachineFunction &MF) {
     WCG = &WCGGFX12Plus;
   } else {
     MaxCounter = NUM_NORMAL_INST_CNTS;
-    WCGPreGFX12 = WaitcntGeneratorPreGFX12(MF);
+    WCGPreGFX12 = WaitcntGeneratorPreGFX12(MF, MaxCounter);
     WCG = &WCGPreGFX12;
   }