MC: Use MCSymbol in MCAsmLayout::getSymbolOffset(), NFC

Continue to canonicalize on MCSymbol instead of MCSymbolData when both
are needed.

llvm-svn: 237749
diff --git a/llvm/lib/MC/MachObjectWriter.cpp b/llvm/lib/MC/MachObjectWriter.cpp
index 002aa3c..12e5a17 100644
--- a/llvm/lib/MC/MachObjectWriter.cpp
+++ b/llvm/lib/MC/MachObjectWriter.cpp
@@ -108,7 +108,7 @@
   }
 
   return getSectionAddress(SD->getFragment()->getParent()) +
-    Layout.getSymbolOffset(SD);
+         Layout.getSymbolOffset(S);
 }
 
 uint64_t MachObjectWriter::getPaddingSize(const MCSectionData *SD,