ipv6: unneccessary to get address prefix in addrconf_get_prefix_route

Since addrconf_get_prefix_route inputs the address prefix to fib6_locate,
which does not uses the data which is out of the prefix_len length,
so do not need to use ipv6_addr_prefix to get address prefix.
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -995,12 +995,9 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
 	 * --yoshfuji
 	 */
 	if ((ifp->flags & IFA_F_PERMANENT) && onlink < 1) {
-		struct in6_addr prefix;
 		struct rt6_info *rt;
 
-		ipv6_addr_prefix(&prefix, &ifp->addr, ifp->prefix_len);
-
-		rt = addrconf_get_prefix_route(&prefix,
+		rt = addrconf_get_prefix_route(&ifp->addr,
 					       ifp->prefix_len,
 					       ifp->idev->dev,
 					       0, RTF_GATEWAY | RTF_DEFAULT);