ethernet/sis: Replace synchronize_sched() with synchronize_rcu()

Now that synchronize_rcu() waits for preempt-disable regions of code
as well as RCU read-side critical sections, synchronize_sched() can be
replaced by synchronize_rcu().  This commit therefore makes this change.
Signed-off-by: NPaul E. McKenney <paulmck@linux.ibm.com>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <netdev@vger.kernel.org>

drivers/net/ethernet/sis/sis190.c

@@ -1142,7 +1142,7 @@ static void sis190_down(struct net_device *dev)
 		if (!poll_locked)
 			poll_locked++;
 
-		synchronize_sched();
+		synchronize_rcu();
 
 	} while (SIS_R32(IntrMask));