setting flow spec rules under vswitch configuration

[Or Gerlitz <ogerlitz@mellanox.com>]

Hi Ben,

Looking on kernel ethtool flow steering APIs in the context of a device
which is used as the uplink of a virtual switch, the admin should be able
to provide flow specification and action (e.g drop) that relates to traffic
coming from a specific port of the switch e.g that relates to a certain 
VM,etc.

For that end, we need to be able to specify both the L3/L4 attributes of
the flow and an L2 spec, that is the L2 spec containing the destination MAC
can't be assumed as the one of that device.

Specifically, in struct ethtool_rx_ntuple_flow_spec, I think we should 
let the
to provide an ethhdr even when L3/L4 spec is given, make sense? if yes, how
would you like to see this change, add a union entry that contains both, 
or in
another way?

Or.