[IPV4]: When possible test for IFF_LOOPBACK and not dev == loopback_dev

Now that multiple loopback devices are becoming possible it makes
the code a little cleaner and more maintainable to test if a deivice
is th a loopback device by testing dev->flags & IFF_LOOPBACK instead
of dev == loopback_dev.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index e7f2b02..55d199e 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1059,7 +1059,7 @@
 			in_dev = inetdev_init(dev);
 			if (!in_dev)
 				return notifier_from_errno(-ENOMEM);
-			if (dev == loopback_dev) {
+			if (dev->flags & IFF_LOOPBACK) {
 				IN_DEV_CONF_SET(in_dev, NOXFRM, 1);
 				IN_DEV_CONF_SET(in_dev, NOPOLICY, 1);
 			}
@@ -1075,7 +1075,7 @@
 	case NETDEV_UP:
 		if (dev->mtu < 68)
 			break;
-		if (dev == loopback_dev) {
+		if (dev->flags & IFF_LOOPBACK) {
 			struct in_ifaddr *ifa;
 			if ((ifa = inet_alloc_ifa()) != NULL) {
 				ifa->ifa_local =