PowerPC - fix uninitialized variable warnings. NFCI.

class PPCAsmPrinter : public AsmPrinter {

protected:

  MapVector<const MCSymbol *, MCSymbol *> TOC;

  const PPCSubtarget *Subtarget;

  const PPCSubtarget *Subtarget = nullptr;

  StackMaps SM;

public:

  ///

  class PPCDAGToDAGISel : public SelectionDAGISel {

    const PPCTargetMachine &TM;

    const PPCSubtarget *PPCSubTarget;

    const PPCTargetLowering *PPCLowering;

    unsigned GlobalBaseReg;

    const PPCSubtarget *PPCSubTarget = nullptr;

    const PPCTargetLowering *PPCLowering = nullptr;

    unsigned GlobalBaseReg = 0;

  public:

    explicit PPCDAGToDAGISel(PPCTargetMachine &tm, CodeGenOpt::Level OptLevel)

  SmallVector<ValueBit, 64> Bits;

  bool NeedMask;

  bool NeedMask = false;

  SmallVector<unsigned, 64> RLAmt;

  SmallVector<BitGroup, 16> BitGroups;

  DenseMap<std::pair<SDValue, unsigned>, ValueRotInfo> ValueRots;

  SmallVector<ValueRotInfo, 16> ValueRotsVec;

  SelectionDAG *CurDAG;

  SelectionDAG *CurDAG = nullptr;

public:

  BitPermutationSelector(SelectionDAG *DAG)

  /// MustSaveLR - Indicates whether LR is defined (or clobbered) in the current

  /// function.  This is only valid after the initial scan of the function by

  /// PEI.

  bool MustSaveLR;

  bool MustSaveLR = false;

  /// MustSaveTOC - Indicates that the TOC save needs to be performed in the

  /// prologue of the function. This is typically the case when there are