net: pxa168_eth: Prepare proper libphy handling

Current libphy handling in pxa168_eth lacks proper phy_connect. Prepare
to fix this by first moving phy properties from platform_data to private
driver data.

Tested-by: Antoine Ténart <antoine.tenart@free-electrons.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>