Explicitly change the link state when we assingn an address.

Since we are setting IFF_UP flag on SIOCSIFADDR, it is possible, that
after this link state information still not initialized properly.
This leads to problems with routing, since now interface has
IFCAP_LINKSTATE capability and a route is considered as working only
when interface's link state is in LINK_STATE_UP (see RT_LINK_IS_UP()
macro).

Reported by:	Marek Zarychta
MFC after:	3 days

sys/net/if_loop.c

@@ -380,6 +380,7 @@ loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 	case SIOCSIFADDR:
 		ifp->if_flags |= IFF_UP;
 		ifp->if_drv_flags |= IFF_DRV_RUNNING;
+		if_link_state_change(ifp, LINK_STATE_UP);
 		/*
 		 * Everything else is done at a higher level.
 		 */