PCI: mvebu: Save MSI controller in pci_sys_data

Save MSI controller in pci_sys_data instead of assigning MSI controller
pointer to every PCI bus in .add_bus().

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index cf907fe..9aa810b 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -774,12 +774,6 @@
 	return bus;
 }
 
-static void mvebu_pcie_add_bus(struct pci_bus *bus)
-{
-	struct mvebu_pcie *pcie = sys_to_pcie(bus->sysdata);
-	bus->msi = pcie->msi;
-}
-
 static resource_size_t mvebu_pcie_align_resource(struct pci_dev *dev,
 						 const struct resource *res,
 						 resource_size_t start,
@@ -816,6 +810,10 @@
 
 	memset(&hw, 0, sizeof(hw));
 
+#ifdef CONFIG_PCI_MSI
+	hw.msi_ctrl = pcie->msi;
+#endif
+
 	hw.nr_controllers = 1;
 	hw.private_data   = (void **)&pcie;
 	hw.setup          = mvebu_pcie_setup;
@@ -823,7 +821,6 @@
 	hw.map_irq        = of_irq_parse_and_map_pci;
 	hw.ops            = &mvebu_pcie_ops;
 	hw.align_resource = mvebu_pcie_align_resource;
-	hw.add_bus        = mvebu_pcie_add_bus;
 
 	pci_common_init(&hw);
 }