Make sure to drop the reference taken by of_phy_find_device() during
probe on probe errors and on driver unbind.

Also drop the of_node reference taken by of_parse_phandle() in the same
path.

Fixes: b9b17deb ("net: emac: emac gigabit ethernet controller driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>