net/mlx5e: Refactor eswitch flow attr for destination specific properties

Currently the eswitch flow attr structure stores each destination
specific property in its own specific array.
Group them in an array of destination structures as a pre-step towards
adding additional destination specific field properties.

Signed-off-by: Eli Britstein <elibr@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>