bonding: make __get_active_agg() use bond_for_each_slave()

Currently we're relying on suboptimal construct

for (; aggregator; aggregator = __get_next_agg(aggregator)) {

where aggregator is an argument of __get_active_agg() which is _always_ the
first slave's aggregator - judging by all the callers, comments in the
ad_agg_selection_logic() and by logic.

Convert it to use the standard bond_for_each_slave().

CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: NVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_3ad.c

@@ -720,16 +720,15 @@ static u32 __get_agg_bandwidth(struct aggregator *aggregator)
  */
 static struct aggregator *__get_active_agg(struct aggregator *aggregator)
 {
-	struct aggregator *retval = NULL;
+	struct bonding *bond = aggregator->slave->bond;
+	struct list_head *iter;
+	struct slave *slave;
 
-	for (; aggregator; aggregator = __get_next_agg(aggregator)) {
-		if (aggregator->is_active) {
-			retval = aggregator;
-			break;
-		}
-	}
+	bond_for_each_slave(bond, slave, iter)
+		if (SLAVE_AD_INFO(slave).aggregator.is_active)
+			return &(SLAVE_AD_INFO(slave).aggregator);
 
-	return retval;
+	return NULL;
 }
 
 /**