add possibility to parameterize the link status handling software timer for fiber optic mode

For netX51 in fiber optic mode, a software timer is used to handle link interrupts (due to a known issue with instable link detection). Currently this timer is using a hard coded 300ms timeout.

For specific hardware layouts, this timer needs to use a longer timeout value. In this ticket, a possibility to configure this timer shall be given. Default timeout shall be 300ms.

Configuration shall be done by adding a Profinet-specific, new parameter to  RX_EDD_PARAMETERS_T structure via config.c. If the parameter is not provided, 300ms shall be used. If parameter is provided, the value shall be used instead.