rt2x00: Implement tx power temperature compensation

rt2800 devices should adjust their tx power in accordance with the
eeproms temperature calibration values. Add a new driver callback
gain_calibration that is called every 4 seconds.

The rt2800 gain calibration routine simply runs the tx power
configuration that takes care of calculating the temperature
compensation delta.

We don't need to synchronize the calls to rt2800_config_txpower
as they should all happen from mac80211's single threaded workqueue.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2800lib.h b/drivers/net/wireless/rt2x00/rt2800lib.h
index 0c92d86..f2d1594 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.h
+++ b/drivers/net/wireless/rt2x00/rt2800lib.h
@@ -181,6 +181,7 @@
 void rt2800_reset_tuner(struct rt2x00_dev *rt2x00dev, struct link_qual *qual);
 void rt2800_link_tuner(struct rt2x00_dev *rt2x00dev, struct link_qual *qual,
 		       const u32 count);
+void rt2800_gain_calibration(struct rt2x00_dev *rt2x00dev);
 
 int rt2800_enable_radio(struct rt2x00_dev *rt2x00dev);
 void rt2800_disable_radio(struct rt2x00_dev *rt2x00dev);