net/mlx5: Introducing E-Switch and l2 table

E-Switch is the software entity that represents and manages ConnectX4
inter-HCA ethernet l2 switching.

E-Switch has its own Virtual Ports, each Vport/vNIC/VF can be
connected to the device through a vport of an e-switch.

Each e-switch is managed by one vNIC identified by
HCA_CAP.vport_group_manager (usually it is the PF/vport[0]),
and its main responsibility is to forward each packet to the
right vport.

e-Switch needs to manage its own l2-table and FDB tables.

L2 table is a flow table that is managed by FW, it is needed for
Multi-host (Multi PF) configuration for inter HCA switching between
PFs.

FDB table is a flow table that is totally managed by e-Switch driver,
its main responsibility is to switch packets between e-Swtich internal
vports and uplink vport that belong to the same.

This patch introduces only e-Swtich l2 table management, FDB managemnt
will come later when ethernet SRIOV/VFs will be enabled.

preperation for ethernet sriov and l2 table management.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>