netdev: expose net_device_ops compat as config option

Now that most network device drivers in (all but one in x86_64 allmodconfig)
support net_device_ops. Expose it as a configuration parameter. Still
need to address even older 32 bit drivers, and other arch before
compatiablity can be scheduled for removal in some future release.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>