net: mscc: ocelot: relax ocelot_exclusive_mac_etype_filter_rules()

The issue which led to the introduction of this check was that MAC_ETYPE
rules, such as filters on dst_mac and src_mac, would only match non-IP
frames. There is a knob in VCAP_S2_CFG which forces all IP frames to be
treated as non-IP, which is what we're currently doing if the user
requested a dst_mac filter, in order to maintain sanity.

But that knob is actually per IS2 lookup. And the good thing with
exposing the lookups to the user via tc chains is that we're now able to
offload MAC_ETYPE keys to one lookup, and IP keys to the other lookup.
So let's do that.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>