net: ethernet: ti: ale: modify vlan/mdb api for switchdev

A following patch introduces switchdev functionality, so modify
ALE engine VLANs/MDBs API:
- cpsw_ale_del_mcast(): update so it will remove only selected ports from
mcast port_mask or delete whole mcast record if !port_mask
- cpsw_ale_del_vlan(): update so it will remove only selected ports from
all VLAN record's masks or delete whole VLAN record if !port_mask
- add cpsw_ale_vlan_add_modify() to add or modify existing VLAN record's
masks
- add cpsw_ale_set_unreg_mcast() for enabling unreg mcast on port VLANs

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>