Now that the DSA Ethernet switches are true Linux devices, the CPU
switch is not necessarily the first one. If its address is higher than
the second switch on the same MDIO bus, its index will be 1, not 0.

Avoid any confusion by using dst->cpu_switch instead of dst->ds[0].
Signed-off-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>