staging: comedi: usbduxfast: 'cmd->chanlist_len' was already validataed

Remove the unnecessary check of 'cmd->chanlist_len > 0'. The (*do_cmdtest) already
validated this before the (*do_cmd) was called.
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/usbduxfast.c

@@ -514,7 +514,6 @@ static int usbduxfast_ai_cmd(struct comedi_device *dev,
 	 */
 	devpriv->ignore = PACKETS_TO_IGNORE;
 
-	if (cmd->chanlist_len > 0) {
 	gain = CR_RANGE(cmd->chanlist[0]);
 	for (i = 0; i < cmd->chanlist_len; ++i) {
 		chan = CR_CHAN(cmd->chanlist[i]);
@@ -536,7 +535,6 @@ static int usbduxfast_ai_cmd(struct comedi_device *dev,
 			break;
 		}
 	}
-	}
 	steps = 0;
 	if (cmd->scan_begin_src == TRIG_TIMER) {
 		dev_err(dev->class_dev,