staging: comedi: usbduxfast: remove unused variable in usbduxfastsub_ai_Irq()

The variable 'p' is initialized but never used otherwise, so
remove the unused variable.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/usbduxfast.c

@@ -312,7 +312,6 @@ static void usbduxfastsub_ai_Irq(struct urb *urb)
 	struct usbduxfastsub_s *udfs;
 	struct comedi_device *this_comedidev;
 	struct comedi_subdevice *s;
-	uint16_t *p;
 
 	/* sanity checks - is the urb there? */
 	if (!urb) {
@@ -379,7 +378,6 @@ static void usbduxfastsub_ai_Irq(struct urb *urb)
 		return;
 	}
 
-	p = urb->transfer_buffer;
 	if (!udfs->ignore) {
 		if (!udfs->ai_continous) {
 			/* not continuous, fixed number of samples */