iio: imu: st_lsm6dsx: flip irq return logic

No need for using reverse logic in the irq return,
fix this by flip things around.
Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c

@@ -670,7 +670,7 @@ static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private)
 	count = hw->settings->fifo_ops.read_fifo(hw);
 	mutex_unlock(&hw->fifo_lock);
 
-	return !count ? IRQ_NONE : IRQ_HANDLED;
+	return count ? IRQ_HANDLED : IRQ_NONE;
 }
 
 static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev)