ne2: silence static never defined warnings

These warning originate from 50014f1b

 (ne2: convert to
net_device_ops) which did drop those functions.

drivers/net/ne2.c:140: warning: 'ne_open' declared 'static' but never defined
drivers/net/ne2.c:141: warning: 'ne_close' declared 'static' but never defined

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>