Reorder includes in Target backends to following coding standards. Remove some superfluous forward declarations.

llvm-svn: 152997
diff --git a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
index 42a3e59..f2b842a 100644
--- a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -13,8 +13,8 @@
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "mips-asm-printer"
-#include "Mips.h"
 #include "MipsAsmPrinter.h"
+#include "Mips.h"
 #include "MipsInstrInfo.h"
 #include "MipsMachineFunction.h"
 #include "MipsMCInstLower.h"