wifi: rtl8xxxu: Fix use after rcu_read_unlock in rtl8xxxu_bss_info_changed

Commit a8b5aef2 ("wifi: rtl8xxxu: gen2: Enable 40 MHz channel width")
introduced a line where the pointer returned by ieee80211_find_sta() is
used after rcu_read_unlock().

Move rcu_read_unlock() a bit lower to fix this.

Fixes: a8b5aef2 ("wifi: rtl8xxxu: gen2: Enable 40 MHz channel width")
Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/3c82ad09-7593-3be1-1d2c-e58505fb43cb@gmail.com

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c

@@ -4645,7 +4645,6 @@ rtl8xxxu_bss_info_changed(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			if (sta->deflink.ht_cap.cap &
 			    (IEEE80211_HT_CAP_SGI_40 | IEEE80211_HT_CAP_SGI_20))
 				sgi = 1;
-			rcu_read_unlock();
 
 			highest_rate = fls(ramask) - 1;
 			if (highest_rate < DESC_RATE_MCS0) {
@@ -4670,6 +4669,7 @@ rtl8xxxu_bss_info_changed(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 				else
 					rarpt->txrate.bw = RATE_INFO_BW_20;
 			}
+			rcu_read_unlock();
 			bit_rate = cfg80211_calculate_bitrate(&rarpt->txrate);
 			rarpt->bit_rate = bit_rate;
 			rarpt->desc_rate = highest_rate;