device property: Clarify usage scope of some struct fwnode_handle members

Most of the struct fwnode_handle members are for exclusive use with
device links framework. Clarify this by adding a respective comment.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Link: https://lore.kernel.org/r/20230904104046.1682875-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/fwnode.h

@@ -41,6 +41,8 @@ struct device;
 struct fwnode_handle {
 	struct fwnode_handle *secondary;
 	const struct fwnode_operations *ops;
+
+	/* The below is used solely by device links, don't use otherwise */
 	struct device *dev;
 	struct list_head suppliers;
 	struct list_head consumers;