[cleanup] Fix another place where we were including the tablegen'ed code

of a '.inc' file before including actual headers. In this case we had
both duplicated a header's include and were including a standard header.

llvm-svn: 206840

llvm/lib/Target/NVPTX/NVPTXRegisterInfo.h

@@ -16,11 +16,10 @@
 
 #include "ManagedStringPool.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include <sstream>
 
 #define GET_REGINFO_HEADER
 #include "NVPTXGenRegisterInfo.inc"
-#include "llvm/Target/TargetRegisterInfo.h"
-#include <sstream>
 
 namespace llvm {