f65dedb sd-netlink: always append new bridge FDB entries

1 file Authored by Yu Watanabe 2 years ago, Committed by zbyszek 2 years ago,
    sd-netlink: always append new bridge FDB entries
    
    This partially reverts 192a9d95ea3e058afd824d38a9cea16ad0a84a57 (#19432).
    
    Fixes #20305.
    
    (cherry picked from commit 74c1ab841fbad9d4f237c819577fcd1d46a072b6)