staging: comedi: usbdux: fix errno (EL2NSYNC) check

These should both be checking the -errno.

Reported by: coverity
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/usbdux.c

@@ -513,7 +513,7 @@ static void usbduxsub_ao_isoc_irq(struct urb *urb)
 			dev_err(dev->class_dev,
 				"ao urb resubm failed in int-cont. ret=%d",
 				ret);
-			if (ret == EL2NSYNC)
+			if (ret == -EL2NSYNC)
 				dev_err(dev->class_dev,
 					"buggy USB host controller or bug in IRQ handling!\n");
 
@@ -1294,7 +1294,7 @@ static void usbduxsub_pwm_irq(struct urb *urb)
 			dev_err(dev->class_dev,
 				"pwm urb resubm failed in int-cont. ret=%d",
 				ret);
-			if (ret == EL2NSYNC)
+			if (ret == -EL2NSYNC)
 				dev_err(dev->class_dev,
 					"buggy USB host controller or bug in IRQ handling!\n");