wifi: mac80211: address some kerneldoc warnings

wifi: mac80211: address some kerneldoc warnings

include/net/mac80111.h contains a number of either excess or incorrect
kerneldoc entries for structure members, leading to these warnings:

  ./include/net/mac80211.h:491: warning: Excess struct member 'rssi' description in 'ieee80211_event'
  ./include/net/mac80211.h:491: warning: Excess struct member 'mlme' description in 'ieee80211_event'
  ./include/net/mac80211.h:491: warning: Excess struct member 'ba' description in 'ieee80211_event'
  ./include/net/mac80211.h:777: warning: Excess struct member 'ack_enabled' description in 'ieee80211_bss_conf'
  ./include/net/mac80211.h:1222: warning: Excess struct member 'ampdu_ack_len' description in 'ieee80211_tx_info'
  ./include/net/mac80211.h:1222: warning: Excess struct member 'ampdu_len' description in 'ieee80211_tx_info'
  ./include/net/mac80211.h:1222: warning: Excess struct member 'ack_signal' description in 'ieee80211_tx_info'
  ./include/net/mac80211.h:2920: warning: Excess struct member 'radiotap_he' description in 'ieee80211_hw'

Fix or remove the entries as needed.  This change removes 208 warnings from
a "make htmldocs" build.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://msgid.link/87zfy4bhxo.fsf@meer.lwn.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>