wwan: core: add print for wwan port attach/disconnect

Refer to USB serial device or net device, there is a notice to
let end user know the status of device, like attached or
disconnected. Add attach/disconnect print for wwan device as
well.
Signed-off-by: Slark Xiao <slark_xiao@163.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/20230420023617.3919569-1-slark_xiao@163.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/wwan/wwan_core.c

@@ -492,6 +492,7 @@ struct wwan_port *wwan_create_port(struct device *parent,
 	if (err)
 		goto error_put_device;
 
+	dev_info(&wwandev->dev, "port %s attached\n", dev_name(&port->dev));
 	return port;
 
 error_put_device:
@@ -517,6 +518,8 @@ void wwan_remove_port(struct wwan_port *port)
 
 	skb_queue_purge(&port->rxq);
 	dev_set_drvdata(&port->dev, NULL);
+
+	dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev));
 	device_unregister(&port->dev);
 
 	/* Release related wwan device */