Normalize SourceMgr messages.

- Don't print "Parsing" in front of every message.

 - Take additional "type" argument which is prepended to the message (with ": ")
   if given.

 - Update clients to print errors (warnings) as:
<filename>:<line number>: error(warning): ...


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74489 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-mc/AsmParser.h

@@ -39,7 +39,8 @@ public:
   
 private:
   bool ParseStatement();
-  
+
+  void Warning(SMLoc L, const char *Msg);
   bool Error(SMLoc L, const char *Msg);
   bool TokError(const char *Msg);