ethdev: replace callback getting filter operations

ethdev: replace callback getting filter operations

Since rte_flow is the only API for filtering operations,
the legacy driver interface filter_ctrl was too much complicated
for the simple task of getting the struct rte_flow_ops.

The filter type RTE_ETH_FILTER_GENERIC and
the filter operarion RTE_ETH_FILTER_GET are removed.
The new driver callback flow_ops_get replaces filter_ctrl.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Acked-by: Haiyue Wang <haiyue.wang@intel.com>
Acked-by: Rosen Xu <rosen.xu@intel.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>