fsl/man: Inherit parent device and of_node

Junote Cai reported that he was not able to get a DSA setup involving the
Freescale DPAA/FMAN driver to work and narrowed it down to
of_find_net_device_by_node(). This function requires the network device's
device reference to be correctly set which is the case here, though we have
lost any device_node association there.

The problem is that dpaa_eth_add_device() allocates a "dpaa-ethernet" platform
device, and later on dpaa_eth_probe() is called but SET_NETDEV_DEV() won't be
propagating &pdev->dev.of_node properly. Fix this by inherenting both the parent
device and the of_node when dpaa_eth_add_device() creates the platform device.

Fixes: 39339616 ("fsl/fman: Add FMan MAC driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>