[IPV6] Remove three method declarations in include/net/ndisc.h.

This patch removes two unused method declarations in
include/net/ndisc.h: ndisc_forwarding_on(void) and
ndisc_forwarding_off(void);

Also igmp6_cleanup(void) appears twice in this header, so one
igmp6_cleanup(void) declaration is removed.
Signed-off-by: NRami Rosen <ramirose@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ndisc.h

@@ -102,9 +102,6 @@ extern void			ndisc_send_rs(struct net_device *dev,
 					      struct in6_addr *saddr,
 					      struct in6_addr *daddr);
 
-extern void			ndisc_forwarding_on(void);
-extern void			ndisc_forwarding_off(void);
-
 extern void			ndisc_send_redirect(struct sk_buff *skb,
 						    struct neighbour *neigh,
 						    struct in6_addr *target);
@@ -124,7 +121,6 @@ extern int			igmp6_event_query(struct sk_buff *skb);
 
 extern int			igmp6_event_report(struct sk_buff *skb);
 
-extern void			igmp6_cleanup(void);
 
 #ifdef CONFIG_SYSCTL
 extern int 			ndisc_ifinfo_sysctl_change(struct ctl_table *ctl,