ath6kl: Introduce spinlock to protect vif specific information

Use this spinlock to protect the vif's data instead of
one from ath6kl.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.c b/drivers/net/wireless/ath/ath6kl/cfg80211.c
index b242b31..d5957b3 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c
@@ -2077,6 +2077,7 @@
 	setup_timer(&vif->disconnect_timer, disconnect_timer_handler,
 		    (unsigned long) vif->ndev);
 	set_bit(WMM_ENABLED, &vif->flags);
+	spin_lock_init(&vif->if_lock);
 
 	return 0;
 }