check the return value of of_address_to_resource() and also add
missing of_node_put() for np and npp nodes.

Fixes: e0a3bc65 ("net: emaclite: Support multiple phys connected to one MDIO bus")
Addresses-Coverity: Event check_return value.
Signed-off-by: Shravya Kumbham <shravya.kumbham@xilinx.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>