net/mlx5: fix entry size in construct data ipool

net/mlx5: fix entry size in construct data ipool

The mlx5_action_construct_data structure memory is managed by ipool
named acts_ipool.

The size of one entry in this ipool is mistakenly defined as size of
rte_flow_hw structure.
This size is used to reset in the allocated part. When the size is
incorrect it resets memory that does not belong to it.

This patch defines the correct size.

Fixes: f13fab23922b ("net/mlx5: add flow jump action")
Cc: stable@dpdk.org
Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>