net: mscc: ocelot: refactor policer work out of ocelot_setup_tc_cls_matchall

In preparation for adding port mirroring support to the ocelot driver,
the dispatching function ocelot_setup_tc_cls_matchall() must be free of
action-specific code. Move port policer creation and deletion to
separate functions.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>