libata: make ata_pci_init_one() not use ops->irq_handler and pi->sht

ata_pci_init_one() is the only function which uses ops->irq_handler
and pi->sht.  Other initialization functions take the same information
as arguments.  This causes confusion and duplicate unused entries in
structures.

Make ata_pci_init_one() take sht as an argument and use ata_interrupt
implicitly.  All current users use ata_interrupt and if different irq
handler is necessary open coding ata_pci_init_one() using
ata_prepare_sff_host() and ata_activate_sff_host can be done under ten
lines including error handling and driver which requires custom
interrupt handler is likely to require custom initialization anyway.

As ata_pci_init_one() was the last user of ops->irq_handler, this
patch also kills the field.

Signed-off-by: Tejun Heo <htejun@gmail.com>

drivers/ata/pata_cmd640.c

@@ -211,7 +211,6 @@ static void cmd640_hardware_init(struct pci_dev *pdev)
 static int cmd640_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	static const struct ata_port_info info = {
-		.sht = &cmd640_sht,
 		.flags = ATA_FLAG_SLAVE_POSS,
 		.pio_mask = 0x1f,
 		.port_ops = &cmd640_port_ops
@@ -225,7 +224,7 @@ static int cmd640_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	cmd640_hardware_init(pdev);
 
-	return ata_pci_init_one(pdev, ppi);
+	return ata_pci_init_one(pdev, ppi, &cmd640_sht);
 }
 
 #ifdef CONFIG_PM