mac80211: remove the repeated declaration

Function 'ieee80211_sta_set_rx_nss' is declared twice, so remove the
repeated declaration.
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Link: https://lore.kernel.org/r/1622196424-62403-1-git-send-email-zhangshaokun@hisilicon.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ieee80211_i.h

@@ -1875,7 +1875,6 @@ void ieee80211_sta_set_rx_nss(struct sta_info *sta);
 enum ieee80211_sta_rx_bandwidth
 ieee80211_chan_width_to_rx_bw(enum nl80211_chan_width width);
 enum nl80211_chan_width ieee80211_sta_cap_chan_bw(struct sta_info *sta);
-void ieee80211_sta_set_rx_nss(struct sta_info *sta);
 void ieee80211_process_mu_groups(struct ieee80211_sub_if_data *sdata,
 				 struct ieee80211_mgmt *mgmt);
 u32 __ieee80211_vht_handle_opmode(struct ieee80211_sub_if_data *sdata,