net/sfc/base: import filters support

net/sfc/base: import filters support

Filtering capabilities depend on NIC family and used firmware
variant. Provided API allows to get supported filter types
(in a priority order), add/delete individual filters and
restore entire filter table after, for example, NIC management
CPU reboot.

Rx filters allow to redirect matching flow to specified Rx queue.

Tx filters allow to control generated traffic (e.g. to implement
virtual function anti-spoofing control).

EFSYS_OPT_FILTER should be enabled to use it. It is required
for SFN7xxx and SFN8xxx adapter families support.

From Solarflare Communications Inc.

Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>