iio: common: scmi_sensors: simplify timestamp channel definition

Use IIO_CHAN_SOFT_TIMESTAMP() to define the timestamp channel instead of
manually filling in the struct iio_chan_spec fields. This makes the code
less verbose and mistake-prone.

In fact, there was an error here as the sign should be 's' instead of
'u' which is now changed to 's' by using IIO_CHAN_SOFT_TIMESTAMP().

If we find that this breaks userspace, we will have to revert this
change, but seems unlikely since the timestamp channel is well-known to
be a signed 64-bit integer globally.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Author: dlech

drivers/iio/common/scmi_sensors/scmi_iio.c

@@ -419,17 +419,6 @@ static const struct iio_chan_spec_ext_info scmi_iio_ext_info[] = {
 	{ }
 };
 
-static void scmi_iio_set_timestamp_channel(struct iio_chan_spec *iio_chan,
-					   int scan_index)
-{
-	iio_chan->type = IIO_TIMESTAMP;
-	iio_chan->channel = -1;
-	iio_chan->scan_index = scan_index;
-	iio_chan->scan_type.sign = 'u';
-	iio_chan->scan_type.realbits = 64;
-	iio_chan->scan_type.storagebits = 64;
-}
-
 static void scmi_iio_set_data_channel(struct iio_chan_spec *iio_chan,
 				      enum iio_chan_type type,
 				      enum iio_modifier mod, int scan_index)
@@ -629,7 +618,7 @@ scmi_alloc_iiodev(struct scmi_device *sdev,
 					 "Error in registering sensor update notifier for sensor %s\n",
 					 sensor->sensor_info->name);
 
-	scmi_iio_set_timestamp_channel(&iio_channels[i], i);
+	iio_channels[i] = IIO_CHAN_SOFT_TIMESTAMP(i);
 	iiodev->channels = iio_channels;
 	return iiodev;
 }