staging: comedi: das16: remove unnecessary test in das16_interrupt()

The timer is only started by the ai subdevice in das16_cmd_exec()
and this function can only be called if the device is attached.

Remove the unnecessary sanity check.

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/das16.c

@@ -350,21 +350,14 @@ static int disable_dma_on_even(struct comedi_device *dev)
 static void das16_interrupt(struct comedi_device *dev)
 {
 	struct das16_private_struct *devpriv = dev->private;
-	unsigned long dma_flags, spin_flags;
 	struct comedi_subdevice *s = dev->read_subdev;
-	struct comedi_async *async;
-	struct comedi_cmd *cmd;
+	struct comedi_async *async = s->async;
+	struct comedi_cmd *cmd = &async->cmd;
+	unsigned long spin_flags;
+	unsigned long dma_flags;
 	int num_bytes, residue;
 	int buffer_index;
 
-	if (!dev->attached) {
-		comedi_error(dev, "premature interrupt");
-		return;
-	}
-	/*  initialize async here to make sure it is not NULL */
-	async = s->async;
-	cmd = &async->cmd;
-
 	spin_lock_irqsave(&dev->spinlock, spin_flags);
 	if ((devpriv->ctrl_reg & DMA_ENABLE) == 0) {
 		spin_unlock_irqrestore(&dev->spinlock, spin_flags);