ath9k: Fix a dma warning/memory leak

proper dma_unmapping and freeing of skb's has to be done in the rx
cleanup for EDMA chipsets when the device is unloaded and this also
seems to address the following warning which shows up occasionally when
the device is unloaded

	Call Trace:
	[<c0148cd2>] warn_slowpath_common+0x72/0xa0
	[<c03b669c>] ? dma_debug_device_change+0x19c/0x200
	[<c03b669c>] ? dma_debug_device_change+0x19c/0x200
	[<c0148da3>] warn_slowpath_fmt+0x33/0x40
	[<c03b669c>] dma_debug_device_change+0x19c/0x200
	[<c0657f12>] notifier_call_chain+0x82/0xb0
	[<c0171370>] __blocking_notifier_call_chain+0x60/0x90
	[<c01713bf>] blocking_notifier_call_chain+0x1f/0x30
	[<c044f594>] __device_release_driver+0xa4/0xc0
	[<c044f647>] driver_detach+0x97/0xa0
	[<c044e65c>] bus_remove_driver+0x6c/0xe0
	[<c029af0b>] ? sysfs_addrm_finish+0x4b/0x60
	[<c0450109>] driver_unregister+0x49/0x80
	[<c0299f54>] ? sysfs_remove_file+0x14/0x20
	[<c03c3ab2>] pci_unregister_driver+0x32/0x80
	[<f92c2162>] ath_pci_exit+0x12/0x20 [ath9k]
	[<f92c8467>] ath9k_exit+0x17/0x36 [ath9k]
	[<c06523cd>] ? mutex_unlock+0xd/0x10
	[<c018e27f>] sys_delete_module+0x13f/0x200
	[<c02139bb>] ? sys_munmap+0x4b/0x60
	[<c06547c5>] ? restore_all+0xf/0xf
	[<c0657a20>] ? spurious_fault+0xe0/0xe0
	[<c01832f4>] ? trace_hardirqs_on_caller+0xf4/0x180
	[<c065b863>] sysenter_do_call+0x12/0x38
	 ---[ end trace 16e1c1521c06bcf9 ]---
	Mapped at:
	[<c03b7938>] debug_dma_map_page+0x48/0x120
	[<f92ba3e8>] ath_rx_init+0x3f8/0x4b0 [ath9k]
	[<f92b5ae4>] ath9k_init_device+0x4c4/0x7b0 [ath9k]
	[<f92c2813>] ath_pci_probe+0x263/0x330 [ath9k]
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/recv.c

@@ -205,14 +205,22 @@ static void ath_rx_remove_buffer(struct ath_softc *sc,
 
 static void ath_rx_edma_cleanup(struct ath_softc *sc)
 {
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath_buf *bf;
 
 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_LP);
 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_HP);
 
 	list_for_each_entry(bf, &sc->rx.rxbuf, list) {
-		if (bf->bf_mpdu)
+		if (bf->bf_mpdu) {
+			dma_unmap_single(sc->dev, bf->bf_buf_addr,
+					common->rx_bufsize,
+					DMA_BIDIRECTIONAL);
 			dev_kfree_skb_any(bf->bf_mpdu);
+			bf->bf_buf_addr = 0;
+			bf->bf_mpdu = NULL;
+		}
 	}
 
 	INIT_LIST_HEAD(&sc->rx.rxbuf);