mac80211: implement nan_change_conf

Implement nan_change_conf callback which allows to change current
NAN configuration (master preference and dual band operation).
Store the current NAN configuration in sdata, so it can be used
both to provide the driver the updated configuration with changes
and also it will be used in hw reconfig flows in next patches.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -3423,6 +3423,12 @@ enum ieee80211_reconfig_type {
  *
  * @start_nan: join an existing NAN cluster, or create a new one.
  * @stop_nan: leave the NAN cluster.
+ * @nan_change_conf: change NAN configuration. The data in cfg80211_nan_conf
+ *	contains full new configuration and changes specify which parameters
+ *	are changed with respect to the last NAN config.
+ *	The driver gets both full configuration and the changed parameters since
+ *	some devices may need the full configuration while others need only the
+ *	changed parameters.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw,
@@ -3664,6 +3670,9 @@ struct ieee80211_ops {
 			 struct cfg80211_nan_conf *conf);
 	int (*stop_nan)(struct ieee80211_hw *hw,
 			struct ieee80211_vif *vif);
+	int (*nan_change_conf)(struct ieee80211_hw *hw,
+			       struct ieee80211_vif *vif,
+			       struct cfg80211_nan_conf *conf, u32 changes);
 };
 
 /**