ath10k: Fix an error handling path

If 'ath10k_usb_create()' fails, we should release some resources and report
an error instead of silently continuing.

Fixes: 4db6649 ("ath10k: add initial USB support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201122170342.1346011-1-christophe.jaillet@wanadoo.fr

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

@@ -997,6 +997,8 @@ static int ath10k_usb_probe(struct usb_interface *interface,
 
 	ar_usb = ath10k_usb_priv(ar);
 	ret = ath10k_usb_create(ar, interface);
+	if (ret)
+		goto err;
 	ar_usb->ar = ar;
 
 	ar->dev_id = product_id;