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

For later use, this patch is renaming ndisc_dst_alloc()
(and related function/structures) to icmp6_dst_alloc()
(and so on).  This patch also removing unused function-
pointer argument for it.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 8db5f4a..eb32295 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -462,7 +462,7 @@
 	icmpv6_flow_init(ndisc_socket->sk, &fl, type,
 			 saddr, daddr, dev->ifindex);
 
-	dst = ndisc_dst_alloc(dev, neigh, daddr, ip6_output);
+	dst = icmp6_dst_alloc(dev, neigh, daddr);
 	if (!dst)
 		return;