bonding: remove bond_vlan_used()

We're using it currently to verify if we have vlans before getting the tag
from the skb we're about to send. It's useless because the vlan_get_tag()
verifies if the skb has the tag (and returns an error if not), and we can
receive tagged skbs only if we *already* have vlans.

Plus, the current RCUed implementation is kind of useless anyway - the we
can remove the last vlan in the moment we return from the function.

So remove the only usage of it and the whole function.

CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 0182352..27b03fa 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -694,10 +694,8 @@
 			client_info->ntt = 0;
 		}
 
-		if (bond_vlan_used(bond)) {
-			if (!vlan_get_tag(skb, &client_info->vlan_id))
-				client_info->tag = 1;
-		}
+		if (!vlan_get_tag(skb, &client_info->vlan_id))
+			client_info->tag = 1;
 
 		if (!client_info->assigned) {
 			u32 prev_tbl_head = bond_info->rx_hashtbl_used_head;