rt2x00: use correct headroom for transmission

Use rt2x00dev->ops->extra_tx_headroom, not rt2x00dev->hw->extra_tx_headroom
in the tx code, as the later may include other headroom not to be used in
the chipset driver.
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00queue.c

@@ -104,7 +104,7 @@ void rt2x00queue_map_txskb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb)
 	 * is also mapped to the DMA so it can be used for transfering
 	 * additional descriptor information to the hardware.
 	 */
-	skb_push(skb, rt2x00dev->hw->extra_tx_headroom);
+	skb_push(skb, rt2x00dev->ops->extra_tx_headroom);
 
 	skbdesc->skb_dma =
 	    dma_map_single(rt2x00dev->dev, skb->data, skb->len, DMA_TO_DEVICE);
@@ -112,7 +112,7 @@ void rt2x00queue_map_txskb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb)
 	/*
 	 * Restore data pointer to original location again.
 	 */
-	skb_pull(skb, rt2x00dev->hw->extra_tx_headroom);
+	skb_pull(skb, rt2x00dev->ops->extra_tx_headroom);
 
 	skbdesc->flags |= SKBDESC_DMA_MAPPED_TX;
 }
@@ -134,7 +134,7 @@ void rt2x00queue_unmap_skb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb)
 		 * by the driver, but it was actually mapped to DMA.
 		 */
 		dma_unmap_single(rt2x00dev->dev, skbdesc->skb_dma,
-				 skb->len + rt2x00dev->hw->extra_tx_headroom,
+				 skb->len + rt2x00dev->ops->extra_tx_headroom,
 				 DMA_TO_DEVICE);
 		skbdesc->flags &= ~SKBDESC_DMA_MAPPED_TX;
 	}