ide: fix hwif->gendev refcounting

class->dev_release is called by device_release() iff dev->release
is not present so ide_port_class_release() is never called and the
last hwif->gendev reference is not dropped.

Fix it by removing ide_port_class_release() and get_device() call
from ide_register_port() (device_create_drvdata() takes a hwif->gendev
reference anyway).

This patch fixes hang on wait_for_completion(&hwif->gendev_rel_comp)
in ide_unregister() reported by Pavel Machek.

Cc: Pavel Machek <pavel@suse.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-probe.c

@@ -646,8 +646,6 @@ static int ide_register_port(ide_hwif_t *hwif)
 		goto out;
 	}
 
-	get_device(&hwif->gendev);
-
 	hwif->portdev = device_create_drvdata(ide_port_class, &hwif->gendev,
 					      MKDEV(0, 0), hwif, hwif->name);
 	if (IS_ERR(hwif->portdev)) {

drivers/ide/ide.c

@@ -1094,13 +1094,6 @@ struct bus_type ide_bus_type = {
 
 EXPORT_SYMBOL_GPL(ide_bus_type);
 
-static void ide_port_class_release(struct device *portdev)
-{
-	ide_hwif_t *hwif = dev_get_drvdata(portdev);
-
-	put_device(&hwif->gendev);
-}
-
 int ide_vlb_clk;
 EXPORT_SYMBOL_GPL(ide_vlb_clk);
 
@@ -1305,7 +1298,6 @@ static int __init ide_init(void)
 		ret = PTR_ERR(ide_port_class);
 		goto out_port_class;
 	}
-	ide_port_class->dev_release = ide_port_class_release;
 
 	init_ide_data();