[IPV4]: Fix issue reported by Coverity in ipv4/fib_frontend.c

fib_del_ifaddr() dereferences ifa->ifa_dev, so the code already assumes that
ifa->ifa_dev is non-NULL, the check is unnecessary.

Signed-off-by: Jayachandran C. <c.jayachandran at gmail.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

net/ipv4/fib_frontend.c

@@ -591,7 +591,7 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event,
 		break;
 	case NETDEV_DOWN:
 		fib_del_ifaddr(ifa);
-		if (ifa->ifa_dev && ifa->ifa_dev->ifa_list == NULL) {
+		if (ifa->ifa_dev->ifa_list == NULL) {
 			/* Last address was deleted from this interface.
 			   Disable IP.
 			 */