iwlwifi: keep plcp_delta_threshold in priv

The base_params shouldn't be writable, so keep
a copy of this in priv that can be modified.

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-rx.c b/drivers/net/wireless/iwlwifi/iwl-agn-rx.c
index d16e73d..5c9c88b 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rx.c
@@ -320,7 +320,7 @@
 				 unsigned int msecs)
 {
 	int delta;
-	int threshold = cfg(priv)->base_params->plcp_delta_threshold;
+	int threshold = priv->plcp_delta_threshold;
 
 	if (threshold == IWL_MAX_PLCP_ERR_THRESHOLD_DISABLE) {
 		IWL_DEBUG_RADIO(priv, "plcp_err check disabled\n");