PCI: Set default bridge parent device

The host bridge's parent device is always the platform device. As we
already have a pointer to it in the devres functions, let's initialize
the parent device. Drivers can still override the parent if desired.

Link: https://lore.kernel.org/r/20200722022514.1283916-3-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/controller/pcie-xilinx-nwl.c

@@ -854,7 +854,6 @@ static int nwl_pcie_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	bridge->dev.parent = dev;
 	bridge->sysdata = pcie;
 	bridge->busnr = pcie->root_busno;
 	bridge->ops = &nwl_pcie_ops;