net/mlx5e: Handle offloads flows per peer

Currently, E-switch offloads table have a list of all flows that
create a peer_flow over the peer eswitch.
In order to support more than one peer, extend E-switch offloads
table peer_flow to hold an array of lists, where each peer have
dedicate index via mlx5_get_dev_index(). Thereafter, extend original
flow to hold an array of peers as well.

Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>