ath9k: Remove bf_dmacontext.

The bf_dmacontext seems to be totally useless and duplicated
by bf_buf_addr.  Remove it entirely, use bf_buf_addr in its
place.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 9b17108..b053058 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -294,7 +294,6 @@
 	tbf->bf_buf_addr = bf->bf_buf_addr;
 	memcpy(tbf->bf_desc, bf->bf_desc, sc->sc_ah->caps.tx_desc_len);
 	tbf->bf_state = bf->bf_state;
-	tbf->bf_dmacontext = bf->bf_dmacontext;
 
 	return tbf;
 }
@@ -1640,17 +1639,15 @@
 
 	bf->bf_mpdu = skb;
 
-	bf->bf_dmacontext = dma_map_single(sc->dev, skb->data,
-					   skb->len, DMA_TO_DEVICE);
-	if (unlikely(dma_mapping_error(sc->dev, bf->bf_dmacontext))) {
+	bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
+					 skb->len, DMA_TO_DEVICE);
+	if (unlikely(dma_mapping_error(sc->dev, bf->bf_buf_addr))) {
 		bf->bf_mpdu = NULL;
 		ath_print(ath9k_hw_common(sc->sc_ah), ATH_DBG_FATAL,
 			  "dma_mapping_error() on TX\n");
 		return -ENOMEM;
 	}
 
-	bf->bf_buf_addr = bf->bf_dmacontext;
-
 	bf->bf_tx_aborted = false;
 
 	return 0;
@@ -1914,7 +1911,7 @@
 			tx_flags |= ATH_TX_XRETRY;
 	}
 
-	dma_unmap_single(sc->dev, bf->bf_dmacontext, skb->len, DMA_TO_DEVICE);
+	dma_unmap_single(sc->dev, bf->bf_buf_addr, skb->len, DMA_TO_DEVICE);
 
 	if (bf->bf_state.bfs_paprd) {
 		if (time_after(jiffies,