iwlwifi: put use_rts_for_aggregation into hw_params

The hardware config ht_params shouldn't be modified,
so copy the use_rts_for_aggregation parameter into
hw_params and use/modify it there.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-mac80211.c b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
index 3086176..d2c1d71 100644
--- a/drivers/net/wireless/iwlwifi/iwl-mac80211.c
+++ b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
@@ -660,8 +660,8 @@
 			IWL_DEBUG_HT(priv, "priv->agg_tids_count = %u\n",
 				     priv->agg_tids_count);
 		}
-		if (!priv->agg_tids_count && cfg(priv)->ht_params &&
-		    cfg(priv)->ht_params->use_rts_for_aggregation) {
+		if (!priv->agg_tids_count &&
+		    hw_params(priv).use_rts_for_aggregation) {
 			/*
 			 * switch off RTS/CTS if it was previously enabled
 			 */