staging: wfx: simplify handling of tx_lock in wfx_do_join()

In the old days, wfx_do_join() could be called from different contexts.
Now that wfx_do_join() is called only from one place, it is cleaner to
keep lock and unlock of data inside the function.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20191217161318.31402-30-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/sta.c

@@ -644,7 +644,6 @@ static void wfx_set_mfp(struct wfx_vif *wvif,
 	hif_set_mfp(wvif, mfpc, mfpr);
 }
 
-/* MUST be called with tx_lock held!  It will be unlocked for us. */
 static void wfx_do_join(struct wfx_vif *wvif)
 {
 	const u8 *bssid;
@@ -659,6 +658,8 @@ static void wfx_do_join(struct wfx_vif *wvif)
 						      conf->basic_rates),
 	};
 
+	wfx_tx_lock_flush(wvif->wdev);
+
 	if (wvif->channel->flags & IEEE80211_CHAN_NO_IR)
 		join.probe_for_join = 0;
 
@@ -1180,10 +1181,8 @@ void wfx_bss_info_changed(struct ieee80211_hw *hw,
 	}
 	mutex_unlock(&wdev->conf_mutex);
 
-	if (do_join) {
-		wfx_tx_lock_flush(wdev);
-		wfx_do_join(wvif); /* Will unlock it for us */
-	}
+	if (do_join)
+		wfx_do_join(wvif);
 }
 
 static void wfx_ps_notify(struct wfx_vif *wvif, enum sta_notify_cmd notify_cmd,