of_net: Fix missing of_find_device_by_node ref count drop

of_find_device_by_node takes a reference to the embedded struct device
which needs to be dropped after use.

Fixes: d01f449c ("of_net: add NVMEM support to of_get_mac_address")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/of/of_net.c

@@ -60,10 +60,13 @@ static const void *of_get_mac_addr_nvmem(struct device_node *np)
 		return ERR_PTR(-ENODEV);
 
 	ret = nvmem_get_mac_address(&pdev->dev, &nvmem_mac);
-	if (ret)
+	if (ret) {
+		put_device(&pdev->dev);
 		return ERR_PTR(ret);
+	}
 
 	mac = devm_kmemdup(&pdev->dev, nvmem_mac, ETH_ALEN, GFP_KERNEL);
+	put_device(&pdev->dev);
 	if (!mac)
 		return ERR_PTR(-ENOMEM);