ath10k: fix memory leak

In ath10k_usb_hif_tx_sg the allocated urb should be released if
usb_submit_urb fails.
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath10k/usb.c

@@ -435,6 +435,7 @@ static int ath10k_usb_hif_tx_sg(struct ath10k *ar, u8 pipe_id,
 			ath10k_dbg(ar, ATH10K_DBG_USB_BULK,
 				   "usb bulk transmit failed: %d\n", ret);
 			usb_unanchor_urb(urb);
+			usb_free_urb(urb);
 			ret = -EINVAL;
 			goto err_free_urb_to_pipe;
 		}