staging:iio:adc:ad7606 remove unnecessary work pending test

Remove unnecessary work pending test before calling schedule_work().
It has been tested in queue_work_on() already. No functional changed.
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/adc/ad7606_core.c

@@ -425,7 +425,6 @@ static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
 	struct ad7606_state *st = iio_priv(indio_dev);
 
 	if (iio_buffer_enabled(indio_dev)) {
-		if (!work_pending(&st->poll_work))
 		schedule_work(&st->poll_work);
 	} else {
 		st->done = true;