mlxsw: core: Add port type (Eth/IB) set API

Add "port_type_set" API to mlxsw core. The core layer send the change type
callback to the port along with it's private information.

Signed-off-by: Elad Raz <eladr@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>