can: usb_8dev: do not report txerr and rxerr during bus-off

During bus off, the error count is greater than 255 and can not fit in
a u8.

Fixes: 0024d8ad ("can: usb_8dev: Add support for USB2CAN interface from 8 devices")
Link: https://lore.kernel.org/all/20220719143550.3681-10-mailhol.vincent@wanadoo.frSigned-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/usb_8dev.c

@@ -438,9 +438,10 @@ static void usb_8dev_rx_err_msg(struct usb_8dev_priv *priv,
 
 	if (rx_errors)
 		stats->rx_errors++;
-
-	cf->data[6] = txerr;
-	cf->data[7] = rxerr;
+	if (priv->can.state != CAN_STATE_BUS_OFF) {
+		cf->data[6] = txerr;
+		cf->data[7] = rxerr;
+	}
 
 	priv->bec.txerr = txerr;
 	priv->bec.rxerr = rxerr;