fs_enet: Don't call NAPI functions when NAPI is not used.

fs_enet_close() calls napi_disable() unconditionally. This patch skips the
call when use_napi isn't set.
Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/fs_enet/fs_enet-main.c

@@ -835,6 +835,7 @@ static int fs_enet_close(struct net_device *dev)
 
 	netif_stop_queue(dev);
 	netif_carrier_off(dev);
+	if (fep->fpi->use_napi)
 		napi_disable(&fep->napi);
 	phy_stop(fep->phydev);