net/mlx5e: CT: Add initial support for Hardware Steering

net/mlx5e: CT: Add initial support for Hardware Steering

Connection tracking can offload tuple matches to the NIC either via
firmware commands (when the steering mode is dmfs or offload support is
disabled due to eswitch being set to legacy) or via software-managed
flow steering (smfs).

This commit adds stub operations for a third mode, hardware-managed flow
steering. This is enabled when both CONFIG_MLX5_TC_CT and
CONFIG_MLX5_HW_STEERING are enabled.

Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Jianbo Liu <jianbol@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20250114130646.1937192-3-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>