ide: ide_unregister() locking bugfix

Holding ide_lock for ide_release_dma_engine() call is unnecessary
and triggers WARN_ON(irqs_disabled()) in dma_free_coherent().
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide.c

@@ -352,15 +352,15 @@ void ide_unregister(ide_hwif_t *hwif)
 	blk_unregister_region(MKDEV(hwif->major, 0), MAX_DRIVES<<PARTN_BITS);
 	kfree(hwif->sg_table);
 	unregister_blkdev(hwif->major, hwif->name);
-	spin_lock_irq(&ide_lock);
 
 	if (hwif->dma_base)
 		ide_release_dma_engine(hwif);
 
+	spin_lock_irq(&ide_lock);
 	/* restore hwif data to pristine status */
 	ide_init_port_data(hwif, hwif->index);
-
 	spin_unlock_irq(&ide_lock);
+
 	mutex_unlock(&ide_cfg_mtx);
 }