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/MipsMCInstLower.cpp b/lib/Target/Mips/MipsMCInstLower.cpp
index 6143eaa..a3f2966 100644
--- a/lib/Target/Mips/MipsMCInstLower.cpp
+++ b/lib/Target/Mips/MipsMCInstLower.cpp
@@ -1,4 +1,4 @@
-//===-- MipsMCInstLower.cpp - Convert Mips MachineInstr to MCInst ---------===//
+//=== MipsMCInstLower.cpp - Convert Mips MachineInstr to MCInst -*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //