wireless: radiotap: fix some kernel-doc

The vendor namespaces argument isn't described here, add it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20200924192511.2bf5cc761d3a.I9b4579ab3eebe3d7889b59eea8fa50d683611bab@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/radiotap.c

@@ -59,6 +59,7 @@ static const struct ieee80211_radiotap_namespace radiotap_ns = {
  * @iterator: radiotap_iterator to initialize
  * @radiotap_header: radiotap header to parse
  * @max_length: total length we can parse into (eg, whole packet length)
+ * @vns: vendor namespaces to parse
  *
  * Returns: 0 or a negative error code if there is a problem.
  *