mac80211: fix csa_counter_offs argument name in docbook

The csa_counter_offs was erroneously described as csa_offs in
the docbook section.

This fixes two warnings when making htmldocs (at least):

Warning(include/net/mac80211.h:3428): No description found for parameter 'csa_counter_offs[IEEE80211_MAX_CSA_COUNTERS_NUM]'
Warning(include/net/mac80211.h:3428): Excess struct/union/enum/typedef member 'csa_offs' description in 'ieee80211_mutable_offsets'
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -3417,8 +3417,9 @@ void ieee80211_report_low_ack(struct ieee80211_sta *sta, u32 num_packets);
  * struct ieee80211_mutable_offsets - mutable beacon offsets
  * @tim_offset: position of TIM element
  * @tim_length: size of TIM element
- * @csa_offs: array of IEEE80211_MAX_CSA_COUNTERS_NUM offsets to CSA counters.
- *	This array can contain zero values which should be ignored.
+ * @csa_counter_offs: array of IEEE80211_MAX_CSA_COUNTERS_NUM offsets
+ *	to CSA counters.  This array can contain zero values which
+ *	should be ignored.
  */
 struct ieee80211_mutable_offsets {
 	u16 tim_offset;