net/mlx5: Add bulk allocation and modify_dek operation

To support fast update of keys into hardware, we optimize firmware to
achieve the maximum rate. The approach is to create DEK objects in
bulk, and update each of them with modify command.
This patch supports bulk allocation and modify_dek commands for new
firmware. However, as log_obj_range is 0 for now, only one DEK obj is
allocated each time, and then updated with user key by modify_dek.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>