fix fallout from the removal of dkio.h from ioctl.h

sysutils/grub/patches/patch-lib_device_c

@@ -0,0 +1,13 @@
+$OpenBSD: patch-lib_device_c,v 1.1 2010/05/20 15:41:33 naddy Exp $
+--- lib/device.c.orig	Thu May 20 09:39:45 2010
++++ lib/device.c	Thu May 20 09:40:43 2010
+@@ -115,6 +115,9 @@ get_kfreebsd_version ()
+ # include <sys/ioctl.h>		/* ioctl */
+ # include <sys/disklabel.h>
+ # include <sys/cdio.h>		/* CDIOCCLRDEBUG */
++# if defined(__OpenBSD__)
++#  include <sys/dkio.h>
++# endif
+ # if defined(__FreeBSD_kernel__)
+ #  include <sys/param.h>
+ #  if __FreeBSD_kernel_version >= 500040