Consolidate some TableGen diagnostic helper functions.

TableGen had diagnostic printers sprinkled about in a few places. Pull them
together into a single location in Error.cpp.

llvm-svn: 133568
diff --git a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
index a08cde6..1930a96 100644
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeGenDAGPatterns.h"
+#include "Error.h"
 #include "Record.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/STLExtras.h"