nd6 DAD: Remove useless casts

[Klemens Nanni]

All *dp variables are of type 'struct dadq *' already;  no object change.

OK?

diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
index 0cd55d966a1..15d7b253c01 100644
--- a/sys/netinet6/nd6_nbr.c
+++ b/sys/netinet6/nd6_nbr.c
@@ -1112,7 +1112,7 @@ nd6_dad_start(struct ifaddr *ifa)
        }
        bzero(&dp->dad_timer_ch, sizeof(dp->dad_timer_ch));
 
-       TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
+       TAILQ_INSERT_TAIL(&dadq, dp, dad_list);
        ip6_dad_pending++;
 
        nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", ifa->ifa_ifp->if_xname,
@@ -1150,7 +1150,7 @@ nd6_dad_stop(struct ifaddr *ifa)
 
        nd6_dad_stoptimer(dp);
 
-       TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
+       TAILQ_REMOVE(&dadq, dp, dad_list);
        free(dp, M_IP6NDP, sizeof(*dp));
        dp = NULL;
        ifafree(ifa);
@@ -1197,7 +1197,7 @@ nd6_dad_timer(void *xifa)
                nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
                        ifa->ifa_ifp->if_xname));
 
-               TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
+               TAILQ_REMOVE(&dadq, dp, dad_list);
                free(dp, M_IP6NDP, sizeof(*dp));
                dp = NULL;
                ifafree(ifa);
@@ -1248,7 +1248,7 @@ nd6_dad_timer(void *xifa)
                            inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr,
                                addr, sizeof(addr))));
 
-                       TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
+                       TAILQ_REMOVE(&dadq, dp, dad_list);
                        free(dp, M_IP6NDP, sizeof(*dp));
                        dp = NULL;
                        ifafree(ifa);