net/mlx5: fix flow counters deletion in Verbs

net/mlx5: fix flow counters deletion in Verbs

The Flow counters created with Verbs are erroneously destroyed
in Flow remove function (flow_verbs_remove()). Counter Verbs
handles stored in the translated rule buffer become invalid.
If rule is reapplied with these invalid counter handles the
driver hangs.

The counter should be destroyed with Verbs in the Flow destroy
function. The Flow remove function should keep counters intact.

Fixes: 60bd8c9747e8 ("net/mlx5: add count flow action")
Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>