according to netintro, SIOCSIFDSTADDR is deprecated. only a handful of
old drivers still have code to handle it, so i'd like to clean them up.
tun(4) can go first.

ok?

Index: if_tun.c
===================================================================
RCS file: /cvs/src/sys/net/if_tun.c,v
diff -u -p -r1.241 if_tun.c
--- if_tun.c	10 Oct 2024 06:50:58 -0000	1.241
+++ if_tun.c	15 Oct 2024 03:29:35 -0000
@@ -599,10 +543,6 @@ tun_ioctl(struct ifnet *ifp, u_long cmd,
 			CLR(ifp->if_flags, IFF_RUNNING);
 		break;
 
-	case SIOCSIFDSTADDR:
-		tun_init(sc);
-		TUNDEBUG(("%s: destination address set\n", ifp->if_xname));
-		break;
 	case SIOCSIFMTU:
 		if (ifr->ifr_mtu < ETHERMIN || ifr->ifr_mtu > TUNMRU)
 			error = EINVAL;