net/mlx5: CT: Allow static allocation of mod headers

As each CT rule uses at least 4 modify header actions, each rule
causes at least 3 reallocations by the mod header actions api.

Allow initial static allocation of the mod acts array, and use it for
CT rules. If the static allocation is exceeded go back to dynamic
allocation.

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>