can: kvaser_usb_leaf: Fix wrong CAN state after stopping

0bfd:0124 Kvaser Mini PCI Express 2xHS FW 4.18.778 sends a
CMD_CHIP_STATE_EVENT indicating bus-off after stopping the device,
causing a stopped device to appear as CAN_STATE_BUS_OFF instead of
CAN_STATE_STOPPED.

Fix that by not handling error events on stopped devices.

Fixes: 080f40a6 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Tested-by: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
Link: https://lore.kernel.org/all/20221010185237.319219-8-extja@kvaser.comSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c

@@ -1045,6 +1045,10 @@ static void kvaser_usb_leaf_rx_error(const struct kvaser_usb *dev,
 	leaf = priv->sub_priv;
 	stats = &priv->netdev->stats;
 
+	/* Ignore e.g. state change to bus-off reported just after stopping */
+	if (!netif_running(priv->netdev))
+		return;
+
 	/* Update all of the CAN interface's state and error counters before
 	 * trying any memory allocation that can actually fail with -ENOMEM.
 	 *