modbus_get_indication_timeout - get timeout used to wait for an indication (request received by a server).
The modbus_get_indication_timeout() function shall store the timeout interval
used to wait for an indication in the
Indication is the term used by the Modbus protocol to designate a request
received by the server.
The default value is zero, it means the server will wait forever.
The function shall return 0 if successful. Otherwise it shall return -1 and set errno.