can: gs_usb: gs_usb_set_timestamp(): remove return statements form void function

Remove the return statements from void gs_usb_set_timestamp()
function, as it's not generally useful.

Link: https://lore.kernel.org/all/20230718-gs_usb-cleanups-v1-3-c3b9154ec605@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/gs_usb.c

@@ -520,8 +520,6 @@ static void gs_usb_set_timestamp(struct gs_can *dev, struct sk_buff *skb,
 		timestamp = le32_to_cpu(hf->classic_can_ts->timestamp_us);
 
 	gs_usb_skb_set_timestamp(dev, skb, timestamp);
-
-	return;
 }
 
 static void gs_usb_receive_bulk_callback(struct urb *urb)