can: gs_usb: gs_can_start_xmit(), gs_can_open(): clean up printouts in error path

Remove unnecessary "out of memory" message from the error path of
gs_can_start_xmit() and gs_can_open().

Convert the printout in case of a failing usb_submit_urb() in
gs_can_open() from numbers to human readable error codes.

Link: https://lore.kernel.org/all/20230718-gs_usb-cleanups-v1-8-c3b9154ec605@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/gs_usb.c

@@ -741,10 +741,8 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
 		goto nomem_urb;
 
 	hf = kmalloc(dev->hf_size_tx, GFP_ATOMIC);
-	if (!hf) {
-		netdev_err(netdev, "No memory left for USB buffer\n");
+	if (!hf)
 		goto nomem_hf;
-	}
 
 	idx = txc->echo_id;
 
@@ -877,8 +875,6 @@ static int gs_can_open(struct net_device *netdev)
 			buf = kmalloc(dev->parent->hf_size_rx,
 				      GFP_KERNEL);
 			if (!buf) {
-				netdev_err(netdev,
-					   "No memory left for USB buffer\n");
 				rc = -ENOMEM;
 				goto out_usb_free_urb;
 			}
@@ -901,7 +897,8 @@ static int gs_can_open(struct net_device *netdev)
 					netif_device_detach(dev->netdev);
 
 				netdev_err(netdev,
-					   "usb_submit failed (err=%d)\n", rc);
+					   "usb_submit_urb() failed, error %pe\n",
+					   ERR_PTR(rc));
 
 				goto out_usb_unanchor_urb;
 			}