r6040: Do a Proper deinit at errorpath and also when driver unloads (calling r6040_remove_one)

so if mdiobus_alloc fails, the errorpath doesnt do a netif_napi_del and also
doesn't set the priv data of the driver to NULL.

at the driver unload stage the driver doesn't remove the NAPI context, and
doesnt' set the priv data to NULL, and also doesn't call the pci_iounmap.

Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>