iio: dac: ad5504: Remove unnecessary cast on void pointer

The following Coccinelle script was used to detect this:
@r@
expression x;
void* e;
type T;
identifier f;
@@
(
  *((T *)e)
|
  ((T *)x)[...]
|
  ((T*)x)->f
|
- (T*)
  e
)

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/dac/ad5504.c

@@ -223,7 +223,7 @@ static irqreturn_t ad5504_event_handler(int irq, void *private)
 					    0,
 					    IIO_EV_TYPE_THRESH,
 					    IIO_EV_DIR_RISING),
-		       iio_get_time_ns((struct iio_dev *)private));
+		       iio_get_time_ns(private));
 
 	return IRQ_HANDLED;
 }