bridge: fdb: Fix FDB dump with strict checking disabled

bridge: fdb: Fix FDB dump with strict checking disabled

While iproute2 correctly uses ifinfomsg struct as the ancillary header
when requesting an FDB dump on old kernels, it sets the message type to
RTM_GETLINK. This results in wrong reply being returned.

Fix this by using RTM_GETNEIGH instead.

Before:
$ bridge fdb show brport dummy0
Not RTM_NEWNEIGH: 00000158 00000010 00000002

After:
$ bridge fdb show brport dummy0
2a:0b:41:1c:92:d3 vlan 1 master br0 permanent
2a:0b:41:1c:92:d3 master br0 permanent
33:33:00:00:00:01 self permanent
01:00:5e:00:00:01 self permanent

Fixes: 05880354c2cf ("bridge: fdb: Fix filtering with strict checking disabled")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reported-by: LiLiang <liali@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Acked-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>