ethernet: stmicro: stmmac: add missing of_node_put after calling of_parse_phandle

of_node_put needs to be called when the device node which is got
from of_parse_phandle has finished using.

This commit fixes both local (in stmmac_axi_setup) and global
(plat->phy_node) device_node for this issue, and using the
correct device node when tries to put node at stmmac_probe_config_dt
for error path.

Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>