iio: imu: adis_buffer: Use new structure for SPI transfer delays

In a recent change to the SPI subsystem [1], a new `delay` struct was added
to replace the `delay_usecs`. This change replaces the current
`delay_usecs` with `delay` for this driver.

The `spi_transfer_delay_exec()` function [in the SPI framework] makes sure
that both `delay_usecs` & `delay` are used (in this order to preserve
backwards compatibility).

[1] commit bebcfd27 ("spi: introduce `delay` field for
`spi_transfer` + spi_transfer_delay_exec()")
Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/adis_buffer.c

@@ -97,7 +97,8 @@ int adis_update_scan_mode(struct iio_dev *indio_dev,
 		if (j != scan_count)
 			adis->xfer[j].cs_change = 1;
 		adis->xfer[j].len = 2;
-		adis->xfer[j].delay_usecs = adis->data->read_delay;
+		adis->xfer[j].delay.value = adis->data->read_delay;
+		adis->xfer[j].delay.unit = SPI_DELAY_UNIT_USECS;
 		if (j < scan_count)
 			adis->xfer[j].tx_buf = &tx[j];
 		if (j >= 1)