DwarfLinker: Use DIEValueList instead of DIE, NFC

Use `DIEValueList` as a pointer to either `DIEBlock` or `DIELoc` instead
of `DIE`, since soon they won't inherit from the latter.

llvm-svn: 243857
diff --git a/llvm/tools/dsymutil/DwarfLinker.cpp b/llvm/tools/dsymutil/DwarfLinker.cpp
index 484c86a..68618bc 100644
--- a/llvm/tools/dsymutil/DwarfLinker.cpp
+++ b/llvm/tools/dsymutil/DwarfLinker.cpp
@@ -2323,7 +2323,7 @@
 unsigned DwarfLinker::cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec,
                                           const DWARFFormValue &Val,
                                           unsigned AttrSize) {
-  DIE *Attr;
+  DIEValueList *Attr;
   DIEValue Value;
   DIELoc *Loc = nullptr;
   DIEBlock *Block = nullptr;
@@ -2335,7 +2335,8 @@
     Block = new (DIEAlloc) DIEBlock;
     DIEBlocks.push_back(Block);
   }
-  Attr = Loc ? static_cast<DIE *>(Loc) : static_cast<DIE *>(Block);
+  Attr = Loc ? static_cast<DIEValueList *>(Loc)
+             : static_cast<DIEValueList *>(Block);
 
   if (Loc)
     Value = DIEValue(dwarf::Attribute(AttrSpec.Attr),