net: tc_act: add helpers to detect ingress mirred actions

TC mirred actions can send to egress or ingress on a given netdev. Helpers
exist to detect actions that are mirred to egress. Extend the header file
to include helpers to detect ingress mirred actions.

Signed-off-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>