net/mlx5: Manage ICM type of SW encap

Support allocate/deallocate the new SW encap ICM type memory.
The new ICM type is used for encap context allocation managed by SW,
instead FW. It can increase encap context maximum number and allocation
speed

Signed-off-by: Shun Hao <shunh@nvidia.com>
Link: https://lore.kernel.org/r/bed5121255918eb132a1334141c76a0594df8143.1701871118.git.leon@kernel.org


Signed-off-by: Leon Romanovsky <leon@kernel.org>