Return LLDP MIB PNO remote entry also for non-Profinet devices

In case a directly connected neighbor is a LLDP capable device but not a Profinet device, Reading the MIB via SNMP will not deliver the LLDP MIB extension lldpXpnoRemPortEntry for this device.

The Profinet certification tests require that this information shall be also returned for non-Profinet devices. Since the values are not known, the default values shall be returned.