wcn36xx: initialize dxe lock

The dxe lock is missing its initialization, so add it.
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/wcn36xx/main.c

@@ -298,6 +298,8 @@ static int wcn36xx_start(struct ieee80211_hw *hw)
 	wcn36xx_debugfs_init(wcn);
 
 	INIT_LIST_HEAD(&wcn->vif_list);
+	spin_lock_init(&wcn->dxe_lock);
+
 	return 0;
 
 out_smd_stop: