net/mlx5e: Only allow offloading decap egress (egdev) flows

We get egress rules through the egdev mechanism when the ingress device
is not supporting offload, with the expected use-case of tunnel decap
ingress rule set on shared tunnel device.

Make sure to offload egress/egdev rules only if decap action (tunnel key
unset) exists there and err otherwise.

Fixes: 717503b9cf57 ("net: sched: convert cls_flower->egress_dev users to tc_setup_cb_egdev infra")
Signed-off-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

@@ -1957,6 +1957,10 @@ static bool actions_match_supported(struct mlx5e_priv *priv,
 	else
 		actions = flow->nic_attr->action;
 
+	if (flow->flags & MLX5E_TC_FLOW_EGRESS &&
+	    !(actions & MLX5_FLOW_CONTEXT_ACTION_DECAP))
+		return false;
+
 	if (actions & MLX5_FLOW_CONTEXT_ACTION_MOD_HDR)
 		return modify_header_match_supported(&parse_attr->spec, exts);