net/mlx5: allocate list memory in create function

net/mlx5: allocate list memory in create function

Currently, the list memory was allocated by the list API caller.

Move it to be allocated by the create API in order to save consistence
with the hlist utility.

Signed-off-by: Matan Azrad <matan@nvidia.com>
Acked-by: Suanming Mou <suanmingm@nvidia.com>