[VLAN]: Don't copy ALLMULTI/PROMISC flags from underlying device

Changing these flags requires to use dev_set_allmulti/dev_set_promiscuity
or dev_change_flags. Setting it directly causes two unwanted effects:

- the next dev_change_flags call will notice a difference between
  dev->gflags and the actual flags, enable promisc/allmulti
  mode and incorrectly update dev->gflags

- this keeps the underlying device in promisc/allmulti mode until
  the VLAN device is deleted

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/8021q/vlan_dev.c

@@ -660,7 +660,7 @@ static int vlan_dev_init(struct net_device *dev)
 	int subclass = 0;
 
 	/* IFF_BROADCAST|IFF_MULTICAST; ??? */
-	dev->flags  = real_dev->flags & ~IFF_UP;
+	dev->flags  = real_dev->flags & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI);
 	dev->iflink = real_dev->ifindex;
 	dev->state  = (real_dev->state & ((1<<__LINK_STATE_NOCARRIER) |
 					  (1<<__LINK_STATE_DORMANT))) |