iio: adis_buffer: update device page after changing it

It makes more sense to update the device page as soon as we we
successfully changed it. Moreover, a follow up patch will handle
'spi_sync' error path which would leave 'current_page' in a inconsistent
state.
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210427085454.30616-3-nuno.sa@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/adis_buffer.c

@@ -140,6 +140,8 @@ static irqreturn_t adis_trigger_handler(int irq, void *p)
 				mutex_unlock(&adis->state_lock);
 				goto irq_done;
 			}
+
+			adis->current_page = 0;
 		}
 	}
 
@@ -148,10 +150,8 @@ static irqreturn_t adis_trigger_handler(int irq, void *p)
 		dev_err(&adis->spi->dev, "Failed to read data: %d", ret);
 
 
-	if (adis->data->has_paging) {
-		adis->current_page = 0;
+	if (adis->data->has_paging)
 		mutex_unlock(&adis->state_lock);
-	}
 
 	iio_push_to_buffers_with_timestamp(indio_dev, adis->buffer,
 		pf->timestamp);