staging: comedi: ni_labpc: remove unnecessary private data validation

The labpc_free_dma_chan() function validates the private data. Remove the
unnecessary validation in labpc_datach().
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/ni_labpc.c

@@ -104,11 +104,7 @@ static int labpc_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 
 static void labpc_detach(struct comedi_device *dev)
 {
-	struct labpc_private *devpriv = dev->private;
-
-	if (devpriv)
 	labpc_free_dma_chan(dev);
-
 	comedi_legacy_detach(dev);
 }