driver core: Clarify documentation for fwnode_operations.add_links()

 *		available suppliers.

 *

 *		Return 0 if device links have been successfully created to all

 *		the suppliers this device needs to create device links to or if

 *		the supplier information is not known.

 *		the known suppliers of this device or if the supplier

 *		information is not known.

 *

 *		Return -ENODEV if and only if the suppliers needed for probing

 *		the device are not yet available to create device links to.

 *		Return -ENODEV if the suppliers needed for probing this device

 *		have not been registered yet (because device links can only be

 *		created to devices registered with the driver core).

 *

 *		Return -EAGAIN if there are suppliers that need to be linked to

 *		that are not yet available but none of those suppliers are

 *		necessary for probing this device.

 *		Return -EAGAIN if some of the suppliers of this device have not

 *		been registered yet, but none of those suppliers are necessary

 *		for probing the device.

 */

struct fwnode_operations {

	struct fwnode_handle *(*get)(struct fwnode_handle *fwnode);