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-agn-rxon.c b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
index 2c5e7ec..e191d39 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
@@ -436,8 +436,7 @@
 	 * force CTS-to-self frames protection if RTS-CTS is not preferred
 	 * one aggregation protection method
 	 */
-	if (!(cfg(priv)->ht_params &&
-	      cfg(priv)->ht_params->use_rts_for_aggregation))
+	if (!hw_params(priv).use_rts_for_aggregation)
 		ctx->staging.flags |= RXON_FLG_SELF_CTS_EN;
 
 	if ((ctx->vif && ctx->vif->bss_conf.use_short_slot) ||