PCI: mvebu: Handle invalid size of read config request

Function mvebu_pcie_hw_rd_conf() does not handle invalid size. So correctly
set read value to all-ones and return appropriate error return value
PCIBIOS_BAD_REGISTER_NUMBER like in mvebu_pcie_hw_wr_conf() function.

Link: https://lore.kernel.org/r/20211125124605.25915-5-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/pci/controller/pci-mvebu.c

@@ -250,6 +250,9 @@ static int mvebu_pcie_hw_rd_conf(struct mvebu_pcie_port *port,
 	case 4:
 		*val = readl_relaxed(conf_data);
 		break;
+	default:
+		*val = 0xffffffff;
+		return PCIBIOS_BAD_REGISTER_NUMBER;
 	}
 
 	return PCIBIOS_SUCCESSFUL;