mac80211: remove PM-QoS listener

As this API has never really seen any use and most drivers don't
ever use the value derived from it, remove it.

Change the only driver using it (rt2x00) to simply use the DTIM
period instead of the "max sleep" time.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 63d03da..276b572 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1428,7 +1428,7 @@
 
 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 	    params->sta_flags_mask & BIT(NL80211_STA_FLAG_AUTHORIZED)) {
-		ieee80211_recalc_ps(local, -1);
+		ieee80211_recalc_ps(local);
 		ieee80211_recalc_ps_vif(sdata);
 	}
 
@@ -2463,7 +2463,7 @@
 	if (ieee80211_hw_check(&local->hw, SUPPORTS_DYNAMIC_PS))
 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 
-	ieee80211_recalc_ps(local, -1);
+	ieee80211_recalc_ps(local);
 	ieee80211_recalc_ps_vif(sdata);
 
 	return 0;