net/mlx5e: Add flow steering DMAC trap rule

Add flow group to the L2 table to hold the catch-all DMAC rule. Add API
which adds/removes DMAC trap rule. This rule catches packets that were
destined to be dropped due to no-match with previous DMAC rules. The
trap rule steer these packets to the trap tir related to the trap-RQ.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>