rtl8xxxu: prevent leaking urb

In rtl8xxxu_submit_int_urb if usb_submit_urb fails the allocated urb
should be released.
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Reviewed-by: Chris Chiu <chiu@endlessm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -5444,6 +5444,7 @@ static int rtl8xxxu_submit_int_urb(struct ieee80211_hw *hw)
 	ret = usb_submit_urb(urb, GFP_KERNEL);
 	if (ret) {
 		usb_unanchor_urb(urb);
+		usb_free_urb(urb);
 		goto error;
 	}