fec: Convert printks to netdev_<level>

Use a more current logging message style.

Convert the printks where a struct net_device is available to
netdev_<level>.  Convert the other printks to pr_<level> and
add pr_fmt where appropriate.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>