xen/pcifront: Rework MSI handling

Replace the about to vanish iterators.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211206210748.251752714@linutronix.de

drivers/pci/xen-pcifront.c

@@ -262,7 +262,7 @@ static int pci_frontend_enable_msix(struct pci_dev *dev,
 	}
 
 	i = 0;
-	for_each_pci_msi_entry(entry, dev) {
+	msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) {
 		op.msix_entries[i].entry = entry->msi_index;
 		/* Vector is useless at this point. */
 		op.msix_entries[i].vector = -1;