Fix copy/paste-o.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155016 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/TableGen/Error.cpp b/lib/TableGen/Error.cpp
index 369e3c1..1463b68 100644
--- a/lib/TableGen/Error.cpp
+++ b/lib/TableGen/Error.cpp
@@ -29,7 +29,7 @@
 }
 
 void PrintWarning(const Twine &Msg) {
-  errs() << "error:" << Msg << "\n";
+  errs() << "warning:" << Msg << "\n";
 }
 
 void PrintWarning(const TGError &Warning) {