staging: fwserial: Fix error handling in fwserial_create

When fw_core_add_address_handler() fails, we need to destroy
the port by tty_port_destroy(). Also we need to unregister
the address handler by fw_core_remove_address_handler() on
failure.
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/r/20201221122437.10274-1-dinghao.liu@zju.edu.cnSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fwserial/fwserial.c

@@ -2189,6 +2189,7 @@ static int fwserial_create(struct fw_unit *unit)
 		err = fw_core_add_address_handler(&port->rx_handler,
 						  &fw_high_memory_region);
 		if (err) {
+			tty_port_destroy(&port->port);
 			kfree(port);
 			goto free_ports;
 		}
@@ -2271,6 +2272,7 @@ static int fwserial_create(struct fw_unit *unit)
 
 free_ports:
 	for (--i; i >= 0; --i) {
+		fw_core_remove_address_handler(&serial->ports[i]->rx_handler);
 		tty_port_destroy(&serial->ports[i]->port);
 		kfree(serial->ports[i]);
 	}