MILexer.h/cpp - remove unused includes. NFC.

Remove duplicates in MILexer.cpp that are already included in MILexer.h.

Author: RKSimon

llvm/lib/CodeGen/MIRParser/MILexer.cpp

@@ -11,12 +11,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "MILexer.h"
-#include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/None.h"
-#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include <algorithm>
 #include <cassert>

llvm/lib/CodeGen/MIRParser/MILexer.h

@@ -15,7 +15,6 @@
 #define LLVM_LIB_CODEGEN_MIRPARSER_MILEXER_H
 
 #include "llvm/ADT/APSInt.h"
-#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include <string>