iwlagn: fix cmd queue unmap

When we stop the device while a command is in
flight that uses multiple TBs, we can leak the
DMA buffers for the second and higher TBs. Fix
this by using iwlagn_unmap_tfd() as we do when
we normally recover the entry.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

drivers/net/wireless/iwlwifi/iwl-tx.c

@@ -309,10 +309,7 @@ void iwl_cmd_queue_unmap(struct iwl_priv *priv)
 		i = get_cmd_index(q, q->read_ptr);
 
 		if (txq->meta[i].flags & CMD_MAPPED) {
-			dma_unmap_single(priv->bus.dev,
-					 dma_unmap_addr(&txq->meta[i], mapping),
-					 dma_unmap_len(&txq->meta[i], len),
-					 DMA_BIDIRECTIONAL);
+			iwlagn_unmap_tfd(priv, &txq->meta[i], &txq->tfds[i]);
 			txq->meta[i].flags = 0;
 		}