PCI: tegra: 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().

[bhelgaas: use struct tegra_msi.chip, not ctrl]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/host/pci-tegra.c

@@ -694,15 +694,6 @@ static int tegra_pcie_map_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
 	return irq;
 }
 
-static void tegra_pcie_add_bus(struct pci_bus *bus)
-{
-	if (IS_ENABLED(CONFIG_PCI_MSI)) {
-		struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata);
-
-		bus->msi = &pcie->msi.chip;
-	}
-}
-
 static struct pci_bus *tegra_pcie_scan_bus(int nr, struct pci_sys_data *sys)
 {
 	struct tegra_pcie *pcie = sys_to_pcie(sys);
@@ -1882,11 +1873,14 @@ static int tegra_pcie_enable(struct tegra_pcie *pcie)
 
 	memset(&hw, 0, sizeof(hw));
 
+#ifdef CONFIG_PCI_MSI
+	hw.msi_ctrl = &pcie->msi.chip;
+#endif
+
 	hw.nr_controllers = 1;
 	hw.private_data = (void **)&pcie;
 	hw.setup = tegra_pcie_setup;
 	hw.map_irq = tegra_pcie_map_irq;
-	hw.add_bus = tegra_pcie_add_bus;
 	hw.scan = tegra_pcie_scan_bus;
 	hw.ops = &tegra_pcie_ops;