au1xxx-ide/rapide: use hwif->index for ide_unregister()

Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/arm/rapide.c

@@ -78,8 +78,8 @@ static void __devexit rapide_remove(struct expansion_card *ec)
 
 	ecard_set_drvdata(ec, NULL);
 
-	/* there must be a better way */
-	ide_unregister(hwif - ide_hwifs);
+	ide_unregister(hwif->index);
+
 	ecard_release_resources(ec);
 }
 

drivers/ide/mips/au1xxx-ide.c

@@ -691,7 +691,7 @@ static int au_ide_remove(struct device *dev)
 	ide_hwif_t *hwif = dev_get_drvdata(dev);
 	_auide_hwif *ahwif = &auide_hwif;
 
-	ide_unregister(hwif - ide_hwifs);
+	ide_unregister(hwif->index);
 
 	iounmap((void *)ahwif->regbase);