net/mlx5: DR, Add modify-header-pattern ICM pool

There is a new ICM area for that memory, so we need to handle it as we
did for the others ICM types.
The patch added that specific pool with its requirements and management.

Signed-off-by: Muhammad Sammar <muhammads@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>