net/mlx5: DR, Init lists that are used in rule's member

Whenever adding new member of rule object we attach it to 2 lists,
These 2 lists should be initialized first.

Fixes: 41d07074

 ("net/mlx5: DR, Expose steering rule functionality")
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>