tc_act: Remove tcf_act macro

tc_act macro addressed a non existing field, and was not used in the
kernel source.

Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>