ahci_platform: enable hotplug unbinding

platform_driver_probe() should be used for registering this driver only
if we want to

    "...remove its run-once probe() infrastructure from memory after the
    driver has bound to the device."

However, we may want to leave the probe infrastructure in place in order
to support binding/unbinding a device dynamically. This is useful, for
instance, as a power management mechanism, where a device can be totally
powered down when unbound (whereas with runtime power management,
powering down the SATA core would incur unacceptable loss of
functionality).

Thus, convert this driver to use platform_driver_register().

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/ahci_platform.c

@@ -75,7 +75,7 @@ static struct scsi_host_template ahci_platform_sht = {
 	AHCI_SHT("ahci_platform"),
 };
 
-static int __init ahci_probe(struct platform_device *pdev)
+static int __devinit ahci_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct ahci_platform_data *pdata = dev_get_platdata(dev);
@@ -326,6 +326,7 @@ static const struct of_device_id ahci_of_match[] = {
 MODULE_DEVICE_TABLE(of, ahci_of_match);
 
 static struct platform_driver ahci_driver = {
+	.probe = ahci_probe,
 	.remove = __devexit_p(ahci_remove),
 	.driver = {
 		.name = "ahci",
@@ -338,7 +339,7 @@ static struct platform_driver ahci_driver = {
 
 static int __init ahci_init(void)
 {
-	return platform_driver_probe(&ahci_driver, ahci_probe);
+	return platform_driver_register(&ahci_driver);
 }
 module_init(ahci_init);