media: imx-mipi-csis: Support active data lanes differing from maximum

Call on v4l2_get_active_data_lanes() to check if the driver reports that
the number of lanes actively used by the MIPI CSI transmitter differs to
the maximum defined in device tree.

If the number of active data lanes reported by the driver is invalid,
catch and return the error. If the operation is not supported, fall back
to the number of allowed data lanes.

Signed-off-by: Isaac Scott <[e-mail]>
Signed-off-by: Sakari Ailus <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/platform/nxp/imx-mipi-csis.c

···
 	format = v4l2_subdev_state_get_format(state, CSIS_PAD_SINK);
 	csis_fmt = find_csis_format(format->code);
 
+	ret = v4l2_get_active_data_lanes(csis->source.pad, csis->bus.num_data_lanes);
+	if (ret < 0)
+		goto err_unlock;
+
+	csis->num_data_lanes = ret;
+
 	ret = mipi_csis_calculate_params(csis, csis_fmt);
 	if (ret < 0)
 		goto err_unlock;