Fix kernel-doc warnings in mac80211.h:

Warning(include/net/mac80211.h:838): No description found for parameter 'ap_addr'
Warning(include/net/mac80211.h:1726): No description found for parameter 'get_survey'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>