Add the private linkage.

llvm-svn: 62279
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 81a1a37..da400a7 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -284,6 +284,7 @@
   case GlobalValue::DLLExportLinkage:    return 6;
   case GlobalValue::ExternalWeakLinkage: return 7;
   case GlobalValue::CommonLinkage:       return 8;
+  case GlobalValue::PrivateLinkage:      return 9;
   }
 }