can: rcar_can: 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: fd115931 ("can: add Renesas R-Car CAN driver")
Link: https://lore.kernel.org/all/20220719143550.3681-3-mailhol.vincent@wanadoo.frSigned-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/rcar/rcar_can.c

@@ -232,11 +232,8 @@ static void rcar_can_error(struct net_device *ndev)
 	if (eifr & (RCAR_CAN_EIFR_EWIF | RCAR_CAN_EIFR_EPIF)) {
 		txerr = readb(&priv->regs->tecr);
 		rxerr = readb(&priv->regs->recr);
-		if (skb) {
+		if (skb)
 			cf->can_id |= CAN_ERR_CRTL;
-			cf->data[6] = txerr;
-			cf->data[7] = rxerr;
-		}
 	}
 	if (eifr & RCAR_CAN_EIFR_BEIF) {
 		int rx_errors = 0, tx_errors = 0;
@@ -336,6 +333,9 @@ static void rcar_can_error(struct net_device *ndev)
 		can_bus_off(ndev);
 		if (skb)
 			cf->can_id |= CAN_ERR_BUSOFF;
+	} else if (skb) {
+		cf->data[6] = txerr;
+		cf->data[7] = rxerr;
 	}
 	if (eifr & RCAR_CAN_EIFR_ORIF) {
 		netdev_dbg(priv->ndev, "Receive overrun error interrupt\n");