PCI/pwrctl: only call of_platform_populate() if CONFIG_OF is enabled

If of_platform_populate() is called when CONFIG_OF is not defined this
leads to spurious error messages of the following type:
 pci 0000:00:01.1: failed to populate child OF nodes (-19)
 pci 0000:00:02.1: failed to populate child OF nodes (-19)

Fixes: 8fb18619 ("PCI/pwrctl: Create platform devices for child OF nodes of the port node")
Signed-off-by: Bert Karwatzki <spasswolf@web.de>
Closes: https://lore.kernel.org/all/20240702173255.39932-1-superm1@kernel.org/Reviewed-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Reported-by: Praveenkumar Patil <PraveenKumar.Patil@amd.com>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20240707183829.41519-1-spasswolf@web.deSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/pci/bus.c

@@ -356,7 +356,7 @@ void pci_bus_add_device(struct pci_dev *dev)
 
 	pci_dev_assign_added(dev, true);
 
-	if (pci_is_bridge(dev)) {
+	if (IS_ENABLED(CONFIG_OF) && pci_is_bridge(dev)) {
 		retval = of_platform_populate(dev->dev.of_node, NULL, NULL,
 					      &dev->dev);
 		if (retval)