rt2x00: add mutex to synchronize config and link tuner

Do not perform mac80211 config and link_tuner at the same time,
this can possibly result in wrong RF or BBP configuration.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c b/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
index 6afd215..8fcbc8d 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
@@ -1313,6 +1313,7 @@ int rt2x00lib_probe_dev(struct rt2x00_dev *rt2x00dev)
 
 	spin_lock_init(&rt2x00dev->irqmask_lock);
 	mutex_init(&rt2x00dev->csr_mutex);
+	mutex_init(&rt2x00dev->conf_mutex);
 	INIT_LIST_HEAD(&rt2x00dev->bar_list);
 	spin_lock_init(&rt2x00dev->bar_list_lock);