bonding: cleanup unneeded rcu_read_lock()

bond_resend_igmp_join_requests_delayed() calls _resend_igmp_join_requests()
under rcu_read_lock(), while it gets its own rcu_read_lock() for the whole
function. Remove the lock from the _delayed function.
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -796,9 +796,8 @@ static void bond_resend_igmp_join_requests_delayed(struct work_struct *work)
 {
 	struct bonding *bond = container_of(work, struct bonding,
 					    mcast_work.work);
-	rcu_read_lock();
+
 	bond_resend_igmp_join_requests(bond);
-	rcu_read_unlock();
 }
 
 /*