cxgb4: remove forgotten unused vlan_group

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/cxgb4/cxgb4.h

@@ -276,7 +276,6 @@ enum {
 };
 
 struct adapter;
-struct vlan_group;
 struct sge_rspq;
 
 struct port_info {