r8169: (re)init phy on resume

Fix switching device to low-speed mode after resume reported in:
https://bugzilla.redhat.com/show_bug.cgi?id=502974

Reported-and-tested-by: Laurentiu Badea <bugzilla-redhat@wotevah.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>