[AVR] Migrate to new MCAsmBackend applyFixup and processFixupValue

[xiangzhai]

Summary

Dear Rafael,

rL305968 applyFixup Data's type was changed to MutableArrayRef<char> so I simply migrated for AVR target, please review my patch, thanks a lot!

Regards,
Leslie Zhai

[xiangzhai]

Removed useless DataSize.

[meadori]

LGTM.

[xiangzhai]

rebase for rL306177 and rL306202 please review it, thanks a lot!

lib/Target/AVR/MCTargetDesc/AVRAsmBackend.h

public:
   AVRAsmBackend(Triple::OSType OSType)
       : MCAsmBackend(), OSType(OSType) {}
 
   void adjustFixupValue(const MCFixup &Fixup, uint64_t &Value,
                         MCContext *Ctx = nullptr) const;
 
   MCObjectWriter *createObjectWriter(raw_pwrite_stream &OS) const override;
 
-  void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
+  void applyFixup(const MCFixup &Fixup, MutableArrayRef<char> Data, unsigned DataSize,
                   uint64_t Value, bool IsPCRel, MCContext &Ctx) const override;
 
   const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
 
   unsigned getNumFixupKinds() const override {
     return AVR::NumTargetFixupKinds;
   }
 

lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp

void AVRAsmBackend::adjustFixupValue(const MCFixup &Fixup, uint64_t &Value,
   }
 }
 
 MCObjectWriter *AVRAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
   return createAVRELFObjectWriter(OS,
                                   MCELFObjectTargetWriter::getOSABI(OSType));
 }
 
-void AVRAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
+void AVRAsmBackend::applyFixup(const MCFixup &Fixup, MutableArrayRef<char> Data,
                                unsigned DataSize, uint64_t Value,
                                bool IsPCRel, MCContext &Ctx) const {
   if (Value == 0)
     return; // Doesn't change encoding.
 
   MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
 
   // The number of bits in the fixup mask