Move dsa slave dedicated code from dsa_switch_destroy to a new
dsa_slave_destroy function in slave.c.
Add the netif_carrier_off and phy_disconnect calls in order to
correctly cleanup the netdev state and PHY state machine.
Signed-off-by: NFrode Isaksen <fisaksen@baylibre.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>