rt2x00: Centralize setting of extra TX headroom requested by rt2x00.

Set the value of extra_tx_headroom in a central place, rather than in each
of the drivers. This is preparatory for taking alignment space into account
in the TX headroom requested by rt2x00.

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>
diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
index 029a45f..dfc886f 100644
--- a/drivers/net/wireless/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/rt2x00/rt2800pci.c
@@ -652,7 +652,7 @@
 {
 	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
 	__le32 *txd = skbdesc->desc;
-	__le32 *txwi = (__le32 *)(skb->data - rt2x00dev->hw->extra_tx_headroom);
+	__le32 *txwi = (__le32 *)(skb->data - rt2x00dev->ops->extra_tx_headroom);
 	u32 word;
 
 	/*
@@ -725,14 +725,14 @@
 	rt2x00_set_field32(&word, TXD_W1_BURST,
 			   test_bit(ENTRY_TXD_BURST, &txdesc->flags));
 	rt2x00_set_field32(&word, TXD_W1_SD_LEN0,
-			   rt2x00dev->hw->extra_tx_headroom);
+			   rt2x00dev->ops->extra_tx_headroom);
 	rt2x00_set_field32(&word, TXD_W1_LAST_SEC0, 0);
 	rt2x00_set_field32(&word, TXD_W1_DMA_DONE, 0);
 	rt2x00_desc_write(txd, 1, word);
 
 	rt2x00_desc_read(txd, 2, &word);
 	rt2x00_set_field32(&word, TXD_W2_SD_PTR1,
-			   skbdesc->skb_dma + rt2x00dev->hw->extra_tx_headroom);
+			   skbdesc->skb_dma + rt2x00dev->ops->extra_tx_headroom);
 	rt2x00_desc_write(txd, 2, word);
 
 	rt2x00_desc_read(txd, 3, &word);
@@ -1207,6 +1207,7 @@
 	.eeprom_size		= EEPROM_SIZE,
 	.rf_size		= RF_SIZE,
 	.tx_queues		= NUM_TX_QUEUES,
+	.extra_tx_headroom	= TXWI_DESC_SIZE,
 	.rx			= &rt2800pci_queue_rx,
 	.tx			= &rt2800pci_queue_tx,
 	.bcn			= &rt2800pci_queue_bcn,