add Emacs tag and fix some comment error in file headers

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150775 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 77cfc37..23d0a6d 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -1,4 +1,4 @@
-//===-- MipsISelLowering.cpp - Mips DAG Lowering Implementation -----------===//
+//=== MipsISelLowering.cpp - Mips DAG Lowering Implementation --*- C++ -*--===//
 //
 //                     The LLVM Compiler Infrastructure
 //