PCI: mvebu: Check valid base address before port setup

This driver does not fail to probe when it cannot obtain
a port base address. Therefore, add a check for NULL base address
before setting up the port, which prevents a kernel panic in such
cases.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index 424a7b8..338691b 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -662,6 +662,8 @@
 
 	for (i = 0; i < pcie->nports; i++) {
 		struct mvebu_pcie_port *port = &pcie->ports[i];
+		if (!port->base)
+			continue;
 		mvebu_pcie_setup_hw(port);
 	}