In the flowtables offload all the devices in the flowtables
share the same flow_block. An offload rule will be installed on
all the devices. This scenario is not correct.

It is no problem if there are only two devices in the flowtable,
The rule with ingress and egress on the same device can be reject
by driver.

But more than two devices in the flowtable will install the wrong
rules on hardware.

For example:
Three devices in a offload flowtables: dev_a, dev_b, dev_c

A rule ingress from dev_a and egress to dev_b:
The rule will install on device dev_a.
The rule will try to install on dev_b but failed for ingress
and egress on the same device.
The rule will install on dev_c. This is not correct.

The flowtables offload avoid this case through restricting the ingress dev
with FLOW_DISSECTOR_KEY_META.

So the mlx5e driver also should support the FLOW_DISSECTOR_KEY_META parse.
Signed-off-by: wenxu <wenxu@ucloud.cn>
Acked-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>