staging: comedi: hwdrv_apci3501: change printk to dev_err

dev_err() is preferred to printk() in device drivers.
Signed-off-by: Chase Southwood <chase.southwood@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/addi-data/hwdrv_apci3501.c

@@ -168,7 +168,7 @@ static int apci3501_read_insn_timer(struct comedi_device *dev,
 
 	else if ((devpriv->b_TimerSelectMode != ADDIDATA_TIMER)
 		&& (devpriv->b_TimerSelectMode != ADDIDATA_WATCHDOG)) {
-		printk("\nIn ReadTimerCounterWatchdog :: Invalid Subdevice \n");
+		dev_err(dev->class_dev, "Invalid subdevice.\n");
 	}
 	return insn->n;
 }