PCI: mvebu: Check that PCI bridge specified in DT has function number zero

Driver cannot handle PCI bridges at non-zero function address. So add
appropriate check. Currently all in-tree kernel DTS files set PCI bridge
function to zero.

Link: https://lore.kernel.org/r/20211125124605.25915-4-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Author: pali

drivers/pci/controller/pci-mvebu.c

@@ -845,6 +845,11 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie,
 	port->devfn = of_pci_get_devfn(child);
 	if (port->devfn < 0)
 		goto skip;
+	if (PCI_FUNC(port->devfn) != 0) {
+		dev_err(dev, "%s: invalid function number, must be zero\n",
+			port->name);
+		goto skip;
+	}
 
 	ret = mvebu_get_tgt_attr(dev->of_node, port->devfn, IORESOURCE_MEM,
 				 &port->mem_target, &port->mem_attr);