netdev: add HAVE_NET_DEVICE_OPS

As a concession to vendors who have to deal with one source for different
kernel versions, add a HAVE_NET_DEVICE_OPS so they don't end up hard
coding ifdef against kernel version.

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

include/linux/netdevice.h

@@ -545,6 +545,7 @@ struct netdev_queue {
  *
  * void (*ndo_poll_controller)(struct net_device *dev);
  */
+#define HAVE_NET_DEVICE_OPS
 struct net_device_ops {
 	int			(*ndo_init)(struct net_device *dev);
 	void			(*ndo_uninit)(struct net_device *dev);