iwlagn: fix priv->cfg->ht_params NULL pointer dereference

This fix regression introduced by commit:

commit 15b3f3b006b42a678523cad989bfd60b76bf4403
Author: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Date:   Fri Jun 3 07:54:13 2011 -0700

    iwlagn: set smps mode after assoc for 1000 device

Also remove unneeded brackets on the way.

Address:
https://bugzilla.redhat.com/show_bug.cgi?id=744155

Cc: stable@kernel.org # 3.1+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-rxon.c

@@ -294,8 +294,8 @@ static int iwlagn_rxon_connect(struct iwl_priv *priv,
 		return ret;
 	}
 
-	if ((ctx->vif && ctx->vif->type == NL80211_IFTYPE_STATION) &&
-	    priv->cfg->ht_params->smps_mode)
+	if (ctx->vif && ctx->vif->type == NL80211_IFTYPE_STATION &&
+	    priv->cfg->ht_params && priv->cfg->ht_params->smps_mode)
 		ieee80211_request_smps(ctx->vif,
 				       priv->cfg->ht_params->smps_mode);