USB: serial: allow subdrivers to modify port-endpoint mapping

Allow subdrivers to modify the port-endpoint mapping by passing the
endpoint descriptors to calc_num_ports.

The callback can now also be used to verify that the required endpoints
exists and abort probing otherwise.

This will allow us to get rid of a few hacks in subdrivers that are
already modifying the port-endpoint mapping (or aborting probe due to
missing endpoints), but only after the port structures have been setup.

Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/mos7720.c

@@ -973,7 +973,8 @@ static void mos7720_bulk_out_data_callback(struct urb *urb)
 		tty_port_tty_wakeup(&mos7720_port->port->port);
 }
 
-static int mos77xx_calc_num_ports(struct usb_serial *serial)
+static int mos77xx_calc_num_ports(struct usb_serial *serial,
+					struct usb_serial_endpoints *epds)
 {
 	u16 product = le16_to_cpu(serial->dev->descriptor.idProduct);
 	if (product == MOSCHIP_DEVICE_ID_7715)