net/mlx5: DR, Add helper to get backing dr table from a mlx5 flow table

If sw steering was used to create the table, dr steeering fs creates
a backing dr table for the mlx5 flow table.

Add helper to return this table so it can be used to create matchers and
add rules on it directly instead of passing via eswitch_offloads/fs_core
insertion.
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_table.c

@@ -305,3 +305,8 @@ u32 mlx5dr_table_get_id(struct mlx5dr_table *tbl)
 {
 	return tbl->table_id;
 }
+
+struct mlx5dr_table *mlx5dr_table_get_from_fs_ft(struct mlx5_flow_table *ft)
+{
+	return ft->fs_dr_table.dr_table;
+}

drivers/net/ethernet/mellanox/mlx5/core/steering/mlx5dr.h

@@ -53,6 +53,9 @@ void mlx5dr_domain_set_peer(struct mlx5dr_domain *dmn,
 struct mlx5dr_table *
 mlx5dr_table_create(struct mlx5dr_domain *domain, u32 level, u32 flags);
 
+struct mlx5dr_table *
+mlx5dr_table_get_from_fs_ft(struct mlx5_flow_table *ft);
+
 int mlx5dr_table_destroy(struct mlx5dr_table *table);
 
 u32 mlx5dr_table_get_id(struct mlx5dr_table *table);