mlxsw: spectrum_nve: Add mlxsw_sp_nve_ops.fdb_replay

A replay of FDB needs to be performed so that the FDB entries existing
at the NVE device are offloaded. How the replay is done depends on NVE
device type, and therefore add a per-NVE-type operation.

Implement the operation for the sole NVE device type currently supported
by mlxsw, VXLAN.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>