If CT fails to initialize it's rhashtables, it doesn't destroy
the ct nat global table.

Destroy the ct nat global table on ct init failure.

Fixes: d7cade51 ("net/mlx5e: check return value of rhashtable_init")
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>