staging: comedi: drivers: usbduxsigma: Removed variables that is never used

Variable was assigned a value that was never used.
I have also removed all the code that thereby serves no purpose.

This was found using a static code analysis program called cppcheck
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: Bernd Porr <mail@berndporr.me.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/usbduxsigma.c

@@ -214,7 +214,6 @@ static void usbduxsigma_ai_handle_urb(struct comedi_device *dev,
 	struct usbduxsigma_private *devpriv = dev->private;
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
-	unsigned int dio_state;
 	uint32_t val;
 	int ret;
 	int i;
@@ -223,9 +222,6 @@ static void usbduxsigma_ai_handle_urb(struct comedi_device *dev,
 	if (devpriv->ai_counter == 0) {
 		devpriv->ai_counter = devpriv->ai_timer;
 
-		/* get the state of the dio pins to allow external trigger */
-		dio_state = be32_to_cpu(devpriv->in_buf[0]);
-
 		/* get the data from the USB bus and hand it over to comedi */
 		for (i = 0; i < cmd->chanlist_len; i++) {
 			/* transfer data, note first byte is the DIO state */