net/mlx5: Add HW interfaces used by LAG

net/mlx5: Add HW interfaces used by LAG

Exposed LAG commands enum and layouts:
- CREATE_LAG
  HW enters LAG mode:
  RoCE traffic from port two is received on PF0 core dev.
  Allows to set tx_affinity (tx port) for QPs and TISes.
  Allows to port remap QPs and TISes, overriding their
  tx_affinity behavior.

- MODIFY_LAG
  Remap QPs and TISes to another port.

- QUERY_LAG
  Query whether LAG mode is active.

- DESTROY_LAG
  HW exits LAG mode, returning to non-LAG behavior.

- CREATE_VPORT_LAG
  Merge Ethernet flow steering, such that traffic received on port
  two jumps to PF0 root flow table.

  Available only in LAG mode.

- DESTROY_VPORT_LAG
  Ethernet flow steering returns to non-LAG behavior.

Caps added:
- lag_master
  Driver is in charge of managing the LAG.
  This is currently the only option.

- num_lag_ports
  LAG is supported only if this field's value is 2.

Other fields:
- QP/TIS tx port affinity
  During LAG, this field controls on which port a QP or TIS resides.

- TIS strict tx affinity
  When this field is set, the TIS will not be subject to port remap by
  CREATE_LAG/MODIFY_LAG.

- LAG demux flow table
  Flow table used for redirecting non user-space traffic back to
  PF1 root flow table, if the packet was received on port two.

Signed-off-by: Aviv Heller <avivh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>