net/mlx5: manage modify actions with hashed list

net/mlx5: manage modify actions with hashed list

To manage header modify actions mlx5 PMD used the single linked list and
lookup and insertion operations took too long times if there were
millions of objects and this impacted the flow insertion/deletion rate.

In order to optimize the performance the hashed list is engaged. The
list implementation is updated to support non-unique keys with few
collisions.

Signed-off-by: Suanming Mou <suanmingm@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>