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/PowerPC/PPCInstrInfo.h b/lib/Target/PowerPC/PPCInstrInfo.h
index e5f171d..7d49aa1 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.h
+++ b/lib/Target/PowerPC/PPCInstrInfo.h
@@ -15,8 +15,8 @@
 #define POWERPC_INSTRUCTIONINFO_H
 
 #include "PPC.h"
-#include "llvm/Target/TargetInstrInfo.h"
 #include "PPCRegisterInfo.h"
+#include "llvm/Target/TargetInstrInfo.h"
 
 #define GET_INSTRINFO_HEADER
 #include "PPCGenInstrInfo.inc"