Preparation for serial commands support.

cmd.c

 			if ((p = parse_text(line, "Video monitoring outputs: ")))
 				d->mon_outputs.num = strtoul(p, NULL, 10);
 			if ((p = parse_text(line, "Serial ports: ")))
-				d->device.num_serial_ports = strtoul(p, NULL, 10);
+				d->serial.num = strtoul(p, NULL, 10);
 			break;
 		case CMD_NAK:
 			ret = false;

data.h

 	char			model_name[MAX_NAME_LEN];
 	char			unique_id[MAX_NAME_LEN];
 	unsigned int	num_video_processing_units;
-	unsigned int	num_serial_ports;
 };
 
 enum port_lock {
 	struct port_set			inputs;
 	struct port_set			outputs;
 	struct port_set			mon_outputs;
+	struct port_set			serial;
 };
 
 extern int debug;

display.c

 	printf("  | %-26s | %-26s |\n", "Protocol", d->device.protocol_ver);
 	printf("  | %-26s | %-26u |\n", "Video inputs", d->inputs.num);
 	printf("  | %-26s | %-26u |\n", "Video outputs", d->outputs.num);
-	if (d->device.num_serial_ports)
-		printf("  | %-26s | %-26u |\n", "Serial ports", d->device.num_serial_ports);
+	if (d->serial.num)
+		printf("  | %-26s | %-26u |\n", "Serial ports", d->serial.num);
 	if (d->device.num_video_processing_units)
 		printf("  | %-26s | %-26u |\n", "Video processing units", d->device.num_video_processing_units);
 	if (d->mon_outputs.num)

videohubctrl.c

 	check_number_of_ports(&data->inputs);
 	check_number_of_ports(&data->outputs);
 	check_number_of_ports(&data->mon_outputs);
+	check_number_of_ports(&data->serial);
 
 	if (num_parsed_cmds) {
 		unsigned int i;