media: subdev: Use 'shall' instead of 'may' in route validation

Route validation docs use the word 'may'. Change that to 'shall' for
emphasis.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/v4l2-core/v4l2-subdev.c

@@ -1738,7 +1738,7 @@ int v4l2_subdev_routing_validate(struct v4l2_subdev *sd,
 
 		/*
 		 * V4L2_SUBDEV_ROUTING_NO_STREAM_MIX: Streams on the same pad
-		 * may not be routed to streams on different pads.
+		 * shall not be routed to streams on different pads.
 		 */
 		if (disallow & V4L2_SUBDEV_ROUTING_NO_STREAM_MIX) {
 			if (remote_pads[route->sink_pad] != U32_MAX &&

include/media/v4l2-subdev.h

@@ -1642,13 +1642,13 @@ u64 v4l2_subdev_state_xlate_streams(const struct v4l2_subdev_state *state,
  * enum v4l2_subdev_routing_restriction - Subdevice internal routing restrictions
  *
  * @V4L2_SUBDEV_ROUTING_NO_1_TO_N:
- *	an input stream may not be routed to multiple output streams (stream
+ *	an input stream shall not be routed to multiple output streams (stream
  *	duplication)
  * @V4L2_SUBDEV_ROUTING_NO_N_TO_1:
- *	multiple input streams may not be routed to the same output stream
+ *	multiple input streams shall not be routed to the same output stream
  *	(stream merging)
  * @V4L2_SUBDEV_ROUTING_NO_STREAM_MIX:
- *	streams on the same pad may not be routed to streams on different pads
+ *	streams on the same pad shall not be routed to streams on different pads
  * @V4L2_SUBDEV_ROUTING_ONLY_1_TO_1:
  *	only non-overlapping 1-to-1 stream routing is allowed (a combination of
  *	@V4L2_SUBDEV_ROUTING_NO_1_TO_N and @V4L2_SUBDEV_ROUTING_NO_N_TO_1)