net/mlx5e: Basic setup of hairpin object

Add the code to do basic setup for hairpin object which
will later serve offloading TC flows.

This includes calling the mlx5 core to create/destroy the hairpin
pair object and setting the HW transport objects that will be used
for steering matched flows to go through hairpin.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>