ath5k: properly free rx dma descriptors

When freeing rx dma descriptors, use the right buffer size.
Fixes kernel oopses on module unload on ixp4xx and most likely
other platforms as well.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath5k/base.c

@@ -310,6 +310,19 @@ static inline void ath5k_txbuf_free(struct ath5k_softc *sc,
 	bf->skb = NULL;
 }
 
+static inline void ath5k_rxbuf_free(struct ath5k_softc *sc,
+				struct ath5k_buf *bf)
+{
+	BUG_ON(!bf);
+	if (!bf->skb)
+		return;
+	pci_unmap_single(sc->pdev, bf->skbaddr, sc->rxbufsize,
+			PCI_DMA_FROMDEVICE);
+	dev_kfree_skb_any(bf->skb);
+	bf->skb = NULL;
+}
+
+
 /* Queues setup */
 static struct 	ath5k_txq *ath5k_txq_setup(struct ath5k_softc *sc,
 				int qtype, int subtype);
@@ -1343,7 +1356,7 @@ ath5k_desc_free(struct ath5k_softc *sc, struct pci_dev *pdev)
 	list_for_each_entry(bf, &sc->txbuf, list)
 		ath5k_txbuf_free(sc, bf);
 	list_for_each_entry(bf, &sc->rxbuf, list)
-		ath5k_txbuf_free(sc, bf);
+		ath5k_rxbuf_free(sc, bf);
 
 	/* Free memory associated with all descriptors */
 	pci_free_consistent(pdev, sc->desc_len, sc->desc, sc->desc_daddr);