libata-sff: prevent irq descriptions for dummy ports

This is a cosmetic change to prevent libata-sff adding irq
descriptions to dummy ports, since the information, while largely
unused, is erroneous.
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/ata/libata-sff.c

@@ -2447,13 +2447,18 @@ int ata_pci_sff_activate_host(struct ata_host *host,
 		return -ENOMEM;
 
 	if (!legacy_mode && pdev->irq) {
+		int i;
+
 		rc = devm_request_irq(dev, pdev->irq, irq_handler,
 				      IRQF_SHARED, drv_name, host);
 		if (rc)
 			goto out;
 
-		ata_port_desc(host->ports[0], "irq %d", pdev->irq);
-		ata_port_desc(host->ports[1], "irq %d", pdev->irq);
+		for (i = 0; i < 2; i++) {
+			if (ata_port_is_dummy(host->ports[i]))
+				continue;
+			ata_port_desc(host->ports[i], "irq %d", pdev->irq);
+		}
 	} else if (legacy_mode) {
 		if (!ata_port_is_dummy(host->ports[0])) {
 			rc = devm_request_irq(dev, ATA_PRIMARY_IRQ(pdev),