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

llvm-svn: 152997
diff --git a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
index da20274..ba9c779 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -11,8 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "PPC.h"
 #include "PPCTargetMachine.h"
+#include "PPC.h"
 #include "llvm/PassManager.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/CodeGen/Passes.h"