net: Remove netdevice ec_ptr, no longer used.

ECONET is gone, thus this can be deleted as well.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1155,7 +1155,6 @@ struct net_device {
 	struct in_device __rcu	*ip_ptr;	/* IPv4 specific data	*/
 	struct dn_dev __rcu     *dn_ptr;        /* DECnet specific data */
 	struct inet6_dev __rcu	*ip6_ptr;       /* IPv6 specific data */
-	void			*ec_ptr;	/* Econet specific data	*/
 	void			*ax25_ptr;	/* AX.25 specific data */
 	struct wireless_dev	*ieee80211_ptr;	/* IEEE 802.11 specific data,
 						   assign before registering */