ahci: Store irq number in struct ahci_host_priv

Currently, ahci supports only msi and intx. To also support msix the
handling of the irq number need to be changed. The irq number for msix
devices is taken from msi_list instead of pci_dev. Thus, the irq
number of a device needs to be stored in struct ahci_host_priv now.
This allows the host controller to be activated in a generic way.

This change is only intended for ahci drivers. For that reason the irq
number is stored in struct ahci_host_priv used only by ahci drivers.
Thus, the ABI changes only for ahci_host_activate(), but existing ata
drivers (about 50) are unaffected and keep unchanged. All users of
ahci_host_activate() have been updated.

While touching drivers/ata/libahci.c, doing a small code cleanup in
ahci_port_start().

Signed-off-by: Robert Richter <rrichter@cavium.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/acard-ahci.c

@@ -433,6 +433,8 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const struct pci_device_id
 	hpriv = devm_kzalloc(dev, sizeof(*hpriv), GFP_KERNEL);
 	if (!hpriv)
 		return -ENOMEM;
+
+	hpriv->irq = pdev->irq;
 	hpriv->flags |= (unsigned long)pi.private_data;
 
 	if (!(hpriv->flags & AHCI_HFLAG_NO_MSI))
@@ -498,7 +500,7 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const struct pci_device_id
 	acard_ahci_pci_print_info(host);
 
 	pci_set_master(pdev);
-	return ahci_host_activate(host, pdev->irq, &acard_ahci_sht);
+	return ahci_host_activate(host, &acard_ahci_sht);
 }
 
 module_pci_driver(acard_ahci_pci_driver);