Next patch will add offload indication to neighbours, but the indication
should only be altered in case the neighbour was successfully added to /
deleted from the device.

Propagate neighbour update errors, so that they could be taken into
account by the next patch.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>