r8169: improve rtl_remove_one

Don't call netif_napi_del() manually, free_netdev() does this for us.
In addition reorder calls to match reverse order of calls in probe().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>