PCI: tegra: Add missing cleanup in error path and tegra_msi_teardown_irq()

We should call tegra_msi_free() to free the MSI bit if irq_create_mapping()
fails.  And we need to dispose the IRQ mapping during IRQ teardown.

[bhelgaas: made irqd_to_hwirq() change suggested by Thierry]
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Acked-by: NThierry Reding <treding@nvidia.com>

drivers/pci/host/pci-tegra.c

@@ -1170,8 +1170,10 @@ static int tegra_msi_setup_irq(struct msi_chip *chip, struct pci_dev *pdev,
 		return hwirq;
 
 	irq = irq_create_mapping(msi->domain, hwirq);
-	if (!irq)
+	if (!irq) {
+		tegra_msi_free(msi, hwirq);
 		return -EINVAL;
+	}
 
 	irq_set_msi_desc(irq, desc);
 
@@ -1189,8 +1191,10 @@ static void tegra_msi_teardown_irq(struct msi_chip *chip, unsigned int irq)
 {
 	struct tegra_msi *msi = to_tegra_msi(chip);
 	struct irq_data *d = irq_get_irq_data(irq);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
 
-	tegra_msi_free(msi, d->hwirq);
+	irq_dispose_mapping(irq);
+	tegra_msi_free(msi, hwirq);
 }
 
 static struct irq_chip tegra_msi_irq_chip = {