staging: comedi: serial2002: don't assume the number of subdevices to detach

Use the number of subdevices allocated (dev->n_subdevices) in the
(*detach) instead of assuming a given number.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/serial2002.c

@@ -811,7 +811,7 @@ static void serial2002_detach(struct comedi_device *dev)
 	struct comedi_subdevice *s;
 	int i;
 
-	for (i = 0; i < 5; i++) {
+	for (i = 0; i < dev->n_subdevices; i++) {
 		s = &dev->subdevices[i];
 		kfree(s->maxdata_list);
 		kfree(s->range_table_list);