net/sched: flower: Move filter handle initialization earlier

To support miss to action during hardware offload the filter's
handle is needed when setting up the actions (tcf_exts_init()),
and before offloading.

Move filter handle initialization earlier.

Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>