[DebugInfo] Remove DwarfUnit::getDwarfVersion(). NFC.

[ikudrin]

Summary

This helper method was used only in one place, which can easily use the direct call.

[dblaikie]

Sounds good to me

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

bool DwarfCompileUnit::includeMinimalInlineScopes() const {
   return getCUNode()->getEmissionKind() == DICompileUnit::LineTablesOnly ||
          (DD->useSplitDwarf() && !Skeleton);
 }
 
 void DwarfCompileUnit::addAddrTableBase() {
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
   MCSymbol *Label = DD->getAddressPool().getLabel();
   addSectionLabel(getUnitDie(),
-                  getDwarfVersion() >= 5 ? dwarf::DW_AT_addr_base
+                  DD->getDwarfVersion() >= 5 ? dwarf::DW_AT_addr_base
                                              : dwarf::DW_AT_GNU_addr_base,
                   Label, TLOF.getDwarfAddrSection()->getBeginSymbol());
 }
 
 void DwarfCompileUnit::addBaseTypeRef(DIEValueList &Die, int64_t Idx) {
   Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, dwarf::DW_FORM_udata,
                new (DIEValueAllocator) DIEBaseTypeRef(this, Idx));
 }
 

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h

 
 public:
   // Accessors.
   AsmPrinter* getAsmPrinter() const { return Asm; }
   MCSymbol *getEndLabel() const { return EndLabel; }
   uint16_t getLanguage() const { return CUNode->getSourceLanguage(); }
   const DICompileUnit *getCUNode() const { return CUNode; }
 
-  uint16_t getDwarfVersion() const { return DD->getDwarfVersion(); }
-
   /// Return true if this compile unit has something to write out.
   bool hasContent() const { return getUnitDie().hasChildren(); }
 
   /// Get string containing language specific context for a global name.
   ///
   /// Walks the metadata parent chain in a language specific manner (using the
   /// compile unit language) and returns it as a string. This is done at the
   /// metadata level because DIEs may not currently have been added to the