ide: prepare init_irq() for using ide_remove_port_from_hwgroup()

* BUG_ON() early if 'hwif->next == hwif' and there is a 'match' hwgroup.

* Remove printk() for impossible condition and add a BUG_ON(hwgroup->drive)
  to match code in ide_unregister().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-probe.c

@@ -996,6 +996,7 @@ static int init_irq (ide_hwif_t *hwif)
 		spin_lock_irq(&ide_lock);
 		hwif->next = hwgroup->hwif->next;
 		hwgroup->hwif->next = hwif;
+		BUG_ON(hwif->next == hwif);
 		spin_unlock_irq(&ide_lock);
 	} else {
 		hwgroup = kmalloc_node(sizeof(*hwgroup), GFP_KERNEL|__GFP_ZERO,
@@ -1075,7 +1076,6 @@ static int init_irq (ide_hwif_t *hwif)
 out_unlink:
 	spin_lock_irq(&ide_lock);
 	if (hwif->next == hwif) {
-		BUG_ON(match);
 		BUG_ON(hwgroup->hwif != hwif);
 		kfree(hwgroup);
 	} else {
@@ -1085,8 +1085,7 @@ static int init_irq (ide_hwif_t *hwif)
 			g = g->next;
 		g->next = hwif->next;
 		if (hwgroup->hwif == hwif) {
-			/* Impossible. */
-			printk(KERN_ERR "Duh. Uninitialized hwif listed as active hwif.\n");
+			BUG_ON(hwgroup->drive);
 			hwgroup->hwif = g;
 		}
 		BUG_ON(hwgroup->hwif == hwif);