[AMDGPU] Return correct value from SDWA pass

llvm/trunk/lib/Target/AMDGPU/SIPeepholeSDWA.cpp

bool SIPeepholeSDWA::runOnMachineFunction(MachineFunction &MF) {
   for (auto &PotentialPair : PotentialMatches) {
     MachineInstr &PotentialMI = *PotentialPair.first;
     convertToSDWA(PotentialMI, PotentialPair.second);
   }
 
   PotentialMatches.clear();
   SDWAOperands.clear();
 
+  bool Ret = !ConvertedInstructions.empty();
   while (!ConvertedInstructions.empty())
     legalizeScalarOperands(*ConvertedInstructions.pop_back_val());
 
-  return false;
+  return Ret;
 }