cfg80211: drop duplicated documentation of field "reg_notifier"

The field "reg_notifier" was already documented above the definition of
struct wiphy. The comment inside the definition of the struct did not
bring more information.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200221115604.594035-6-Jerome.Pouiller@silabs.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -4676,7 +4676,6 @@ struct wiphy {
 
 	struct ieee80211_supported_band *bands[NUM_NL80211_BANDS];
 
-	/* Lets us get back the wiphy on the callback */
 	void (*reg_notifier)(struct wiphy *wiphy,
 			     struct regulatory_request *request);