rt2x00: move extra_tx_headroom field from rt2x00_ops to rt2x00_dev

The extra_tx_headroom field of struct rt2x00_ops
indicates the extra TX headroom size required for
a given device. This data is redundant, the value
can be computed from the desc_size and winfo_size
fields of the TX queues.

Move the extra_tx_headroom field to struct rt2x00_dev,
compute its value in the probe routine and use the
cached value in the rest of the code.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 2a17f7e..ee3fc57 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -648,7 +648,6 @@
 	const unsigned int eeprom_size;
 	const unsigned int rf_size;
 	const unsigned int tx_queues;
-	const unsigned int extra_tx_headroom;
 	void (*queue_init)(struct data_queue *queue);
 	const struct rt2x00lib_ops *lib;
 	const void *drv;
@@ -1007,6 +1006,9 @@
 	 */
 	struct list_head bar_list;
 	spinlock_t bar_list_lock;
+
+	/* Extra TX headroom required for alignment purposes. */
+	unsigned int extra_tx_headroom;
 };
 
 struct rt2x00_bar_list_entry {