bonding: delete unused ad_timer

Now we use agg_select_timer and ad_work.
Reviewed-by: NWANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: NWeiping Pan <panweiping3@gmail.com>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_3ad.h

@@ -253,7 +253,6 @@ struct ad_system {
 struct ad_bond_info {
 	struct ad_system system;	    /* 802.3ad system structure */
 	u32 agg_select_timer;	    // Timer to select aggregator after all adapter's hand shakes
-	struct timer_list ad_timer;
 };
 
 struct ad_slave_info {