PCI/MSI: xgene: Remove msi_controller assignment

After 8d63bc7b ("PCI/MSI: pci-xgene-msi: Get rid of struct
msi_controller"), it is no longer required to assign msi_controller for
X-Gene PCIe host bridge to support MSI.

Remove this unnecessary code.  This also avoids a warning message ("failed
to enable MSI") during boot.

[bhelgaas: changelog]
Signed-off-by: Duc Dang <dhdang@apm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Tanmay Inamdar <tinamdar@apm.com>

drivers/pci/host/pci-xgene.c

@@ -509,24 +509,6 @@ static int xgene_pcie_setup(struct xgene_pcie_port *port,
 	return 0;
 }
 
-static int xgene_pcie_msi_enable(struct pci_bus *bus)
-{
-	struct device_node *msi_node;
-
-	msi_node = of_parse_phandle(bus->dev.of_node,
-					"msi-parent", 0);
-	if (!msi_node)
-		return -ENODEV;
-
-	bus->msi = of_pci_find_msi_chip_by_node(msi_node);
-	if (!bus->msi)
-		return -ENODEV;
-
-	of_node_put(msi_node);
-	bus->msi->dev = &bus->dev;
-	return 0;
-}
-
 static int xgene_pcie_probe_bridge(struct platform_device *pdev)
 {
 	struct device_node *dn = pdev->dev.of_node;
@@ -567,10 +549,6 @@ static int xgene_pcie_probe_bridge(struct platform_device *pdev)
 	if (!bus)
 		return -ENOMEM;
 
-	if (IS_ENABLED(CONFIG_PCI_MSI))
-		if (xgene_pcie_msi_enable(bus))
-			dev_info(port->dev, "failed to enable MSI\n");
-
 	pci_scan_child_bus(bus);
 	pci_assign_unassigned_bus_resources(bus);
 	pci_bus_add_devices(bus);