brcmfmac: fix setting of station info chains bitmask

The sinfo->chains field is a bitmask for filled values in chain_signal
and chain_signal_avg, not a count. Treat it as such so that the driver
can properly report per-chain RSSI information.

Before (MIMO mode):

  $ iw dev wlan0 station dump
      ...
      signal: -51 [-51] dBm

After (MIMO mode):

  $ iw dev wlan0 station dump
      ...
      signal: -53 [-53, -54] dBm

Fixes: cae355dc ("brcmfmac: Add RSSI information to get_station.")
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210506132010.3964484-1-alsi@bang-olufsen.dk

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c

@@ -2838,6 +2838,7 @@ brcmf_cfg80211_get_station(struct wiphy *wiphy, struct net_device *ndev,
 		count_rssi = 0;
 		for (i = 0; i < BRCMF_ANT_MAX; i++) {
 			if (sta_info_le.rssi[i]) {
+				sinfo->chains |= BIT(count_rssi);
 				sinfo->chain_signal_avg[count_rssi] =
 					sta_info_le.rssi[i];
 				sinfo->chain_signal[count_rssi] =
@@ -2848,8 +2849,6 @@ brcmf_cfg80211_get_station(struct wiphy *wiphy, struct net_device *ndev,
 		}
 		if (count_rssi) {
 			sinfo->filled |= BIT_ULL(NL80211_STA_INFO_CHAIN_SIGNAL);
-			sinfo->chains = count_rssi;
-
 			sinfo->filled |= BIT_ULL(NL80211_STA_INFO_SIGNAL);
 			total_rssi /= count_rssi;
 			sinfo->signal = total_rssi;