nexthop: Remove unused function declaration from header file

Not used or implemented anywhere.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/nexthop.h

@@ -109,9 +109,6 @@ enum nexthop_event_type {
 	NEXTHOP_EVENT_DEL
 };
 
-int call_nexthop_notifier(struct notifier_block *nb, struct net *net,
-			  enum nexthop_event_type event_type,
-			  struct nexthop *nh);
 int register_nexthop_notifier(struct net *net, struct notifier_block *nb);
 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);