[IPV6]: Make ndisc_flow_init() common for later use.

For later use, this patch is renaming ndisc_flow_init() to
icmpv6_flow_init() and putting it in common place.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

include/linux/icmpv6.h

@@ -182,6 +182,14 @@ extern int				icmpv6_err_convert(int type, int code,
 extern void				icmpv6_cleanup(void);
 extern void				icmpv6_param_prob(struct sk_buff *skb,
 							  int code, int pos);
+
+struct flowi;
+extern void				icmpv6_flow_init(struct sock *sk,
+							 struct flowi *fl,
+							 u8 type,
+							 const struct in6_addr *saddr,
+							 const struct in6_addr *daddr,
+							 int oif);
 #endif
 
 #endif