[msf] Rename Msf to MSF.

In a previous patch, it was suggested to use all caps instead of
rolling caps for initialisms, so this patch changes everything
to do this.

llvm-svn: 277190

llvm/lib/DebugInfo/CodeView/ModuleSubstream.cpp

@@ -9,7 +9,7 @@
 
 #include "llvm/DebugInfo/CodeView/ModuleSubstream.h"
 
-#include "llvm/DebugInfo/Msf/StreamReader.h"
+#include "llvm/DebugInfo/MSF/StreamReader.h"
 
 using namespace llvm;
 using namespace llvm::codeview;