ipv6: Use ip6_multipath_hash_policy() in rt6_multipath_hash().

Make use of the new helper.
Suggested-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -1846,7 +1846,7 @@ u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
 	struct flow_keys hash_keys;
 	u32 mhash;
 
-	switch (net->ipv6.sysctl.multipath_hash_policy) {
+	switch (ip6_multipath_hash_policy(net)) {
 	case 0:
 		memset(&hash_keys, 0, sizeof(hash_keys));
 		hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;