ip6_mroute: Remove unnecessary casts

No functional change intended.

MFC after:	1 week
Sponsored by:	Stormshield
Sponsored by:	Klara, Inc.

sys/netinet6/ip6_mroute.c

@@ -916,8 +916,7 @@ add_m6fc(struct mf6cctl *mfccp)
 		}
 		if (rt == NULL) {
 			/* no upcall, so make a new entry */
-			rt = (struct mf6c *)malloc(sizeof(*rt), M_MRTABLE6,
-						  M_NOWAIT);
+			rt = malloc(sizeof(*rt), M_MRTABLE6, M_NOWAIT);
 			if (rt == NULL) {
 				MFC6_UNLOCK();
 				return (ENOBUFS);
@@ -1134,7 +1133,7 @@ X_ip6_mforward(struct ip6_hdr *ip6, struct ifnet *ifp, struct mbuf *m)
 	 * Allocate mbufs early so that we don't do extra work if we
 	 * are just going to fail anyway.
 	 */
-	rte = (struct rtdetq *)malloc(sizeof(*rte), M_MRTABLE6, M_NOWAIT);
+	rte = malloc(sizeof(*rte), M_MRTABLE6, M_NOWAIT);
 	if (rte == NULL) {
 		MFC6_UNLOCK();
 		return (ENOBUFS);
@@ -1168,7 +1167,7 @@ X_ip6_mforward(struct ip6_hdr *ip6, struct ifnet *ifp, struct mbuf *m)
 		struct omrt6msg *oim;
 #endif
 		/* no upcall, so make a new entry */
-		rt = (struct mf6c *)malloc(sizeof(*rt), M_MRTABLE6, M_NOWAIT);
+		rt = malloc(sizeof(*rt), M_MRTABLE6, M_NOWAIT);
 		if (rt == NULL) {
 			free(rte, M_MRTABLE6);
 			m_freem(mb0);