net/mlx5: DR, Initialize chunk's ste_arrays at chunk creation

Rather than cleaning the corresponding chunk's section of ste_arrays on
chunk deletion, initialize these areas upon chunk creation.

Chunk destruction tend to come in large batches (during pool syncing).
To reduce the "hiccup" in such cases, moving ste_arrays init from chunk
destruction to initialization.

Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>