staging: comedi: remove 'bc.subdevice < 0' check in do_bufconfig_ioctl()

Type of variable 'bc' is struct comedi_bufconfig and 'subdevice' is
defined as unsigned, so there is no need to check if it is less then
zero.
Signed-off-by: Güngör Erseymen <gelurine@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedi_fops.c

@@ -660,7 +660,7 @@ static int do_bufconfig_ioctl(struct comedi_device *dev,
 	if (copy_from_user(&bc, arg, sizeof(bc)))
 		return -EFAULT;
 
-	if (bc.subdevice >= dev->n_subdevices || bc.subdevice < 0)
+	if (bc.subdevice >= dev->n_subdevices)
 		return -EINVAL;
 
 	s = &dev->subdevices[bc.subdevice];