staging: comedi: usbduxfast: remove impossible 'if (!devpriv)' checks

The private data 'devpriv' is allocated in the (*auto_attach) before
the subdevices are initialized and the (*auto_attach) has to complete
successfully before the core will call any of the subdevice operations.
Because of this the (!devpriv) checks in the subdevice code can never
fail. Remove them.
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/usbduxfast.c

@@ -223,9 +223,6 @@ static int usbduxfast_ai_cancel(struct comedi_device *dev,
 	struct usbduxfast_private *devpriv = dev->private;
 	int ret;
 
-	if (!devpriv)
-		return -EFAULT;
-
 	down(&devpriv->sem);
 	ret = usbduxfast_ai_stop(dev, 1);
 	up(&devpriv->sem);
@@ -317,9 +314,6 @@ static int usbduxfast_submit_urb(struct comedi_device *dev)
 	struct usbduxfast_private *devpriv = dev->private;
 	int ret;
 
-	if (!devpriv)
-		return -EFAULT;
-
 	usb_fill_bulk_urb(devpriv->urb, usb, usb_rcvbulkpipe(usb, BULKINEP),
 			  devpriv->inbuf, SIZEINBUF,
 			  usbduxfast_ai_interrupt, dev);
@@ -466,9 +460,6 @@ static int usbduxfast_ai_inttrig(struct comedi_device *dev,
 	struct comedi_cmd *cmd = &s->async->cmd;
 	int ret;
 
-	if (!devpriv)
-		return -EFAULT;
-
 	if (trig_num != cmd->start_arg)
 		return -EINVAL;
 
@@ -501,9 +492,6 @@ static int usbduxfast_ai_cmd(struct comedi_device *dev,
 	int result;
 	long steps, steps_tmp;
 
-	if (!devpriv)
-		return -EFAULT;
-
 	down(&devpriv->sem);
 	if (devpriv->ai_cmd_running) {
 		dev_err(dev->class_dev, "ai_cmd not possible\n");