phylib: Support attaching to generic 10g driver

phy_attach_direct() may now attach to a generic 10G driver. It can
also be used exactly as phy_connect_direct(), which will be useful
when using of_mdio, as phy_connect (and therefore of_phy_connect)
start the PHY state machine, which is currently irrelevant for 10G
PHYs.

Signed-off-by: Andy Fleming <afleming@gmail.com>
Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>