rtl8xxxu: Call device specific _config_channel()

Having a version for the newer chips without calling it doesn't do
much good.....
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -7348,7 +7348,7 @@ static int rtl8xxxu_config(struct ieee80211_hw *hw, u32 changed)
 
 		rtl8723a_set_tx_power(priv, channel, ht40);
 
-		rtl8723au_config_channel(hw);
+		priv->fops->config_channel(hw);
 	}
 
 exit: