rtlwifi: rtl8192cu: Prevent leaking urb

If usb_submit_urb fails the allocated urb should be unanchored and
released.
Signed-off-by: Reto Schneider <code@reto-schneider.ch>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200622132113.14508-3-code@reto-schneider.ch

drivers/net/wireless/realtek/rtlwifi/usb.c

@@ -720,8 +720,11 @@ static int _rtl_usb_receive(struct ieee80211_hw *hw)
 
 		usb_anchor_urb(urb, &rtlusb->rx_submitted);
 		err = usb_submit_urb(urb, GFP_KERNEL);
-		if (err)
+		if (err) {
+			usb_unanchor_urb(urb);
+			usb_free_urb(urb);
 			goto err_out;
+		}
 		usb_free_urb(urb);
 	}
 	return 0;