net/sfc: process RSS settings on Rx configure step

net/sfc: process RSS settings on Rx configure step

One may submit advanced RSS settings as part of
rte_eth_conf to customise RSS configuration from
the very beginning. Currently the driver does not
check that piece of settings and proceeds with
default choices for RSS hash functions and RSS key.

This patch implements the required processing.

Fixes: 4ec1fc3ba881 ("net/sfc: add basic stubs for RSS support on driver attach")
Cc: stable@dpdk.org
Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>