bnx2: 64 bit stats on all arches

Now core network is able to handle 64 bit netdevice stats on 32 bit
arches, we can provide them for bnx2, since hardware maintains some 64
bit counters.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>