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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152997 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Hexagon/HexagonCallingConvLower.cpp b/lib/Target/Hexagon/HexagonCallingConvLower.cpp
index 71787de..46c20e9 100644
--- a/lib/Target/Hexagon/HexagonCallingConvLower.cpp
+++ b/lib/Target/Hexagon/HexagonCallingConvLower.cpp
@@ -14,13 +14,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "HexagonCallingConvLower.h"
+#include "Hexagon.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
-#include "Hexagon.h"
 using namespace llvm;
 
 Hexagon_CCState::Hexagon_CCState(CallingConv::ID CC, bool isVarArg,