sfc: Move siena_nic_data::ipv6_rss_key to efx_nic::rx_hash_key

We will use this hash key for Toeplitz IPv4 hashing too.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc drivers/net/sfc/efx.c
Simple merge

diff --cc drivers/net/sfc/net_driver.h
Simple merge

diff --cc drivers/net/sfc/nic.h
Simple merge

diff --cc drivers/net/sfc/siena.c
Simple merge