net/flow_dissector: correct comments on enum flow_dissector_key_id
There are no such structs flow_dissector_key_flow_vlan or
flow_dissector_key_flow_tags, the actual structs used are struct
flow_dissector_key_vlan and struct flow_dissector_key_tags. So correct the
comments against FLOW_DISSECTOR_KEY_VLAN, FLOW_DISSECTOR_KEY_FLOW_LABEL and
FLOW_DISSECTOR_KEY_CVLAN to refer to those.
Signed-off-by: Edward Cree <ecree@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>