ipv4: fix NULL checking in devinet_ioctl()

The NULL pointer check `!ifa' should come before its first use.

[ Bug origin : commit fd23c3b31107e2fc483301ee923d8a1db14e53f4
(ipv4: Add hash table of interface addresses) in linux-2.6.39 ]

Signed-off-by: Xi Wang <[e-mail]>
Acked-by: Eric Dumazet <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/devinet.c

···
 		if (!ifa) {
 			ret = -ENOBUFS;
 			ifa = inet_alloc_ifa();
-			INIT_HLIST_NODE(&ifa->hash);
 			if (!ifa)
 				break;
+			INIT_HLIST_NODE(&ifa->hash);
 			if (colon)
 				memcpy(ifa->ifa_label, ifr.ifr_name, IFNAMSIZ);
 			else