staging: wfx: do not update uapsd if not necessary

wfx_conf_tx() is called for each queue. On every call, the function
updates UAPSD mask and PM mode for all queues. It is a pity since the
UAPSD configuration very rarely changes and it makes exchanges between
the host and the chip more difficult to track.

This patch avoid to update UAPSD and Power Mode in most usual cases.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200115135338.14374-43-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/sta.c

@@ -286,6 +286,7 @@ int wfx_conf_tx(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 {
 	struct wfx_dev *wdev = hw->priv;
 	struct wfx_vif *wvif = (struct wfx_vif *) vif->drv_priv;
+	int old_uapsd = wvif->uapsd_mask;
 	int ret = 0;
 
 	WARN_ON(queue >= hw->queues);
@@ -294,7 +295,8 @@ int wfx_conf_tx(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	assign_bit(queue, &wvif->uapsd_mask, params->uapsd);
 	memcpy(&wvif->edca_params[queue], params, sizeof(*params));
 	hif_set_edca_queue_params(wvif, queue, params);
-	if (wvif->vif->type == NL80211_IFTYPE_STATION) {
+	if (wvif->vif->type == NL80211_IFTYPE_STATION &&
+	    old_uapsd != wvif->uapsd_mask) {
 		hif_set_uapsd_info(wvif, wvif->uapsd_mask);
 		wfx_update_pm(wvif);
 	}