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/Mips/MipsAsmPrinter.h b/lib/Target/Mips/MipsAsmPrinter.h
index 8502db2..473da7e 100644
--- a/lib/Target/Mips/MipsAsmPrinter.h
+++ b/lib/Target/Mips/MipsAsmPrinter.h
@@ -22,9 +22,9 @@
 namespace llvm {
 class MCStreamer;
 class MachineInstr;
-class raw_ostream;
 class MachineBasicBlock;
 class Module;
+class raw_ostream;
 
 class LLVM_LIBRARY_VISIBILITY MipsAsmPrinter : public AsmPrinter {