wl1271: Configure QOS nullfunc template for U-APSD

When U-APSD is enabled, device is not sending power save
state notifications to AP using QOS nullfunc frames.

This patch configures nullfunc templates needed for U-APSD.
Signed-off-by: NSaravanan Dhanabal <ext-saravanan.dhanabal@nokia.com>
Reviewed-by: NJuuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: NLuciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/wl12xx/wl1271_main.c

@@ -1707,6 +1707,10 @@ static void wl1271_op_bss_info_changed(struct ieee80211_hw *hw,
 			if (ret < 0)
 				goto out_sleep;
 
+			ret = wl1271_build_qos_null_data(wl);
+			if (ret < 0)
+				goto out_sleep;
+
 			/* filter out all packets not from this BSSID */
 			wl1271_configure_filters(wl, 0);