llvm-mc: Make MCSymbolData symbol member const.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80573 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 87ea99f..5a7b01b 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -72,7 +72,7 @@
     return *Entry;
   }
 
-  MCSymbolData &getSymbolData(MCSymbol &Symbol) {
+  MCSymbolData &getSymbolData(const MCSymbol &Symbol) {
     MCSymbolData *&Entry = SymbolMap[&Symbol];
 
     if (!Entry)