iio: adc: ti-adc108s102: Fix alignment of buffer pushed to iio buffers.

Use the newly introduce iio_push_to_buffers_with_ts_unaligned() function
to ensure a bounce buffer is used to provide the required alignment and
space padding needed by the IIO core which requires the timestamp
is naturally aligned.  There will be a performance cost to this change
but it will ensure the driver works on platforms that do not support
unaligned 8 byte assignments, and with consumer drivers that may
assume natural alignment of the timestamp.

Issue found as part of an audit of all calls to
iio_push_to_buffers_with_timestamp()

Fixes: 7e87d11c9b ("iio: adc: Add support for TI ADC108S102 and ADC128S102")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Link: https://lore.kernel.org/r/20210613151039.569883-3-jic23@kernel.org

drivers/iio/adc/ti-adc108s102.c

@@ -75,9 +75,9 @@ struct adc108s102_state {
 	 *  rx_buf: |XX|R0|R1|R2|R3|R4|R5|R6|R7|tt|tt|tt|tt|
 	 *
 	 *  tx_buf: 8 channel read commands, plus 1 dummy command
-	 *  rx_buf: 1 dummy response, 8 channel responses, plus 64-bit timestamp
+	 *  rx_buf: 1 dummy response, 8 channel responses
 	 */
-	__be16				rx_buf[13] ____cacheline_aligned;
+	__be16				rx_buf[9] ____cacheline_aligned;
 	__be16				tx_buf[9] ____cacheline_aligned;
 };
 
@@ -149,9 +149,10 @@ static irqreturn_t adc108s102_trigger_handler(int irq, void *p)
 		goto out_notify;
 
 	/* Skip the dummy response in the first slot */
-	iio_push_to_buffers_with_timestamp(indio_dev,
-					   (u8 *)&st->rx_buf[1],
-					   iio_get_time_ns(indio_dev));
+	iio_push_to_buffers_with_ts_unaligned(indio_dev,
+					      &st->rx_buf[1],
+					      st->ring_xfer.len - sizeof(st->rx_buf[1]),
+					      iio_get_time_ns(indio_dev));
 
 out_notify:
 	iio_trigger_notify_done(indio_dev->trig);