Sometimes Topology and Xpno change are not reported to PNS stack

In case of link down or expired TTL LLDP task send a Topology change indication to PNS stack as expected. if after that a no changed LLDP frame is received at the same port the LLDP does not recognize any change in peer data therefore is no change notification is reported. This is because the remote peer data is not cleared when link is down or TTL is expired.