fix include order in sys-i386/registers.c

We want sys/ptrace.h before any includes of linux/ptrace.h and
asm/user.h pulls the latter.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/os-Linux/sys-i386/registers.c

@@ -5,6 +5,7 @@
  */
 
 #include <errno.h>
+#include <sys/ptrace.h>
 #include <asm/user.h>
 #include "kern_constants.h"
 #include "longjmp.h"