[Hexagon][NFC] Drop no-op getMaskedMemoryOpCost/getGatherScatterOpCost stubs (#170426)

These stubs (from 4bdf1aa) don’t actually override anything.
Removing them eliminates the need for a local getMemIntrinsicCost()
forwarder in #169885.

Author: arcbbb

llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp

@@ -223,12 +223,6 @@ InstructionCost HexagonTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
                                 OpInfo, I);
 }
 
-InstructionCost
-HexagonTTIImpl::getMaskedMemoryOpCost(const MemIntrinsicCostAttributes &MICA,
-                                      TTI::TargetCostKind CostKind) const {
-  return BaseT::getMaskedMemoryOpCost(MICA, CostKind);
-}
-
 InstructionCost
 HexagonTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, VectorType *DstTy,
                                VectorType *SrcTy, ArrayRef<int> Mask,
@@ -238,12 +232,6 @@ HexagonTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, VectorType *DstTy,
   return 1;
 }
 
-InstructionCost
-HexagonTTIImpl::getGatherScatterOpCost(const MemIntrinsicCostAttributes &MICA,
-                                       TTI::TargetCostKind CostKind) const {
-  return BaseT::getGatherScatterOpCost(MICA, CostKind);
-}
-
 InstructionCost HexagonTTIImpl::getInterleavedMemoryOpCost(
     unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices,
     Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind,

llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.h

@@ -120,16 +120,10 @@ class HexagonTTIImpl final : public BasicTTIImplBase<HexagonTTIImpl> {
       TTI::OperandValueInfo OpInfo = {TTI::OK_AnyValue, TTI::OP_None},
       const Instruction *I = nullptr) const override;
   InstructionCost
-  getMaskedMemoryOpCost(const MemIntrinsicCostAttributes &MICA,
-                        TTI::TargetCostKind CostKind) const override;
-  InstructionCost
   getShuffleCost(TTI::ShuffleKind Kind, VectorType *DstTy, VectorType *SrcTy,
                  ArrayRef<int> Mask, TTI::TargetCostKind CostKind, int Index,
                  VectorType *SubTp, ArrayRef<const Value *> Args = {},
                  const Instruction *CxtI = nullptr) const override;
-  InstructionCost
-  getGatherScatterOpCost(const MemIntrinsicCostAttributes &MICA,
-                         TTI::TargetCostKind CostKind) const override;
   InstructionCost getInterleavedMemoryOpCost(
       unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices,
       Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind,