staging: comedi: ni_tiocmd: (!foo) preferred over (foo == NULL)

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_tiocmd.c

@@ -201,7 +201,7 @@ int ni_tio_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	unsigned long flags;
 
 	spin_lock_irqsave(&counter->lock, flags);
-	if (counter->mite_chan == NULL) {
+	if (!counter->mite_chan) {
 		dev_err(counter->counter_dev->dev->class_dev,
 			"commands only supported with DMA.  ");
 		dev_err(counter->counter_dev->dev->class_dev,
@@ -329,7 +329,7 @@ static int should_ack_gate(struct ni_gpct *counter)
 	case ni_gpct_variant_e_series:
 		spin_lock_irqsave(&counter->lock, flags);
 		{
-			if (counter->mite_chan == NULL ||
+			if (!counter->mite_chan ||
 			    counter->mite_chan->dir != COMEDI_INPUT ||
 			    (mite_done(counter->mite_chan))) {
 				retval = 1;
@@ -443,7 +443,7 @@ void ni_tio_handle_interrupt(struct ni_gpct *counter,
 		break;
 	}
 	spin_lock_irqsave(&counter->lock, flags);
-	if (counter->mite_chan == NULL) {
+	if (!counter->mite_chan) {
 		spin_unlock_irqrestore(&counter->lock, flags);
 		return;
 	}