net/mlx5: Fix wrong reserved field in hca_cap_2 in mlx5_ifc

Fixing the wrong size of a field in hca_cap_2.
The bug was introduced by adding new fields for HWS
and not fixing the reserved field size.

Fixes: 34c626c3 ("net/mlx5: Added missing mlx5_ifc definition for HW Steering")
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>