iwlwifi: Fix to set correct ht configuration

iwl_set_rxon_ht() only get called in iwl_post_associate(); which cause
possible incorrect ht configuration. Adding the call in iwl_mac_config() if
IEEE80211_CONF_CHANGE_CHANNEL flag is set to re-configure and send rxon
command.

Fixes
http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2146

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
CC: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -2744,6 +2744,7 @@ int iwl_mac_config(struct ieee80211_hw *hw, u32 changed)
 		if ((le16_to_cpu(priv->staging_rxon.channel) != ch))
 			priv->staging_rxon.flags = 0;
 
+		iwl_set_rxon_ht(priv, ht_conf);
 		iwl_set_rxon_channel(priv, conf->channel);
 
 		iwl_set_flags_for_band(priv, conf->channel->band);