USB: serial: visor: drop redundant calc_num_ports callback

Drop the redundant calc_num_ports callback from the clie_5 type, for
which the callback always returns zero and hence falls back to the type
num_ports value (2).
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/visor.c

@@ -197,7 +197,6 @@ static struct usb_serial_driver clie_5_device = {
 	.unthrottle =		usb_serial_generic_unthrottle,
 	.attach =		clie_5_attach,
 	.probe =		visor_probe,
-	.calc_num_ports =	visor_calc_num_ports,
 	.read_int_callback =	visor_read_int_callback,
 };