Use unicast DMAC for IP neighbor pool refresh probes

Change-Id: I12fbebd1d24c37dc77c147773ea522c8a4b7b99d
Signed-off-by: John Lo <loj@cisco.com>
diff --git a/src/vnet/ip/ip6.h b/src/vnet/ip/ip6.h
index 6f6724b..8b1516c 100644
--- a/src/vnet/ip/ip6.h
+++ b/src/vnet/ip/ip6.h
@@ -354,7 +354,7 @@
 int ip6_address_compare (ip6_address_t * a1, ip6_address_t * a2);
 
 clib_error_t *ip6_probe_neighbor (vlib_main_t * vm, ip6_address_t * dst,
-				  u32 sw_if_index);
+				  u32 sw_if_index, u8 refresh);
 
 uword
 ip6_udp_register_listener (vlib_main_t * vm,