Revert "rt2x00: Fix rt2800usb TX descriptor writing."

This reverts commit 663cb47.

This patch was merged out of the proper order, so instead of fixing a
problem with a prior (unmerged) patch, it creates one.  Ooops!

Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800usb.c

@@ -413,7 +413,7 @@ static void rt2800usb_write_tx_desc(struct rt2x00_dev *rt2x00dev,
 	 */
 	rt2x00_desc_read(txi, 0, &word);
 	rt2x00_set_field32(&word, TXINFO_W0_USB_DMA_TX_PKT_LEN,
-			   skb->len - TXINFO_DESC_SIZE);
+			   skb->len + TXWI_DESC_SIZE);
 	rt2x00_set_field32(&word, TXINFO_W0_WIV,
 			   !test_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc->flags));
 	rt2x00_set_field32(&word, TXINFO_W0_QSEL, 2);