powerpc/pseries/msi: Use PCI device properties

instead of fiddling with MSI descriptors.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221813.556202506@linutronix.de

arch/powerpc/platforms/pseries/msi.c

@@ -448,8 +448,7 @@ static int pseries_msi_ops_prepare(struct irq_domain *domain, struct device *dev
 				   int nvec, msi_alloc_info_t *arg)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
-	struct msi_desc *desc = first_pci_msi_entry(pdev);
-	int type = desc->pci.msi_attrib.is_msix ? PCI_CAP_ID_MSIX : PCI_CAP_ID_MSI;
+	int type = pdev->msix_enabled ? PCI_CAP_ID_MSIX : PCI_CAP_ID_MSI;
 
 	return rtas_prepare_msi_irqs(pdev, nvec, type, arg);
 }