libata-acpi: add new hooks ata_acpi_dissociate() and ata_acpi_on_disable()

Add two hooks - ata_acpi_dissociate() which is called during driver
detach after the whole host is shutdown and ata_acpi_on_disable()
which is called when a device is disabled.

Signed-off-by: Tejun heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index c316eac..4af939a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -622,6 +622,7 @@
 	if (ata_dev_enabled(dev)) {
 		if (ata_msg_drv(dev->link->ap))
 			ata_dev_printk(dev, KERN_WARNING, "disabled\n");
+		ata_acpi_on_disable(dev);
 		ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 |
 					     ATA_DNXFER_QUIET);
 		dev->class++;
@@ -7249,6 +7250,9 @@
 
 	for (i = 0; i < host->n_ports; i++)
 		ata_port_detach(host->ports[i]);
+
+	/* the host is dead now, dissociate ACPI */
+	ata_acpi_dissociate(host);
 }
 
 /**