ide: make ide_unregister() take 'ide_hwif_t *' as an argument (take 2)

* Make ide_unregister() take 'ide_hwif_t *hwif' instead of 'unsigned int
  index' (hwif->index) as an argument and update all users accordingly.

While at it:

* Remove unnecessary checks for hwif != NULL from ide-pnp.c::idepnp_remove()
  and delkin_cb.c::delkin_cb_remove().

* Remove needless hwif->chipset assignment from scc_pata.c::scc_remove().

v2:
* Fixup ide_unregister() documentation.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/legacy/ide-cs.c b/drivers/ide/legacy/ide-cs.c
index 867fe14..8753e2d 100644
--- a/drivers/ide/legacy/ide-cs.c
+++ b/drivers/ide/legacy/ide-cs.c
@@ -386,7 +386,7 @@
     if (info->ndev) {
 	/* FIXME: if this fails we need to queue the cleanup somehow
 	   -- need to investigate the required PCMCIA magic */
-	ide_unregister(hwif->index);
+	ide_unregister(hwif);
     }
     info->ndev = 0;