can: sja1000: sja1000_err(): don't count arbitration lose as an error

Losing arbitration is normal in a CAN-bus network, it means that a higher
priority frame is being send and the pending message will be retried later.
Hence most driver only increment arbitration_lost, but the sja1000 driver also
incremeants tx_error, causing errors to be reported on a normal functioning
CAN-bus. So stop counting them as errors.

Fixes: 8935f57e ("can: sja1000: fix network statistics update")
Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>
Link: https://lore.kernel.org/r/20201127095941.21609-1-jhofstee@victronenergy.com
[mkl: split into two seperate patches]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/sja1000/sja1000.c

@@ -474,7 +474,6 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 		netdev_dbg(dev, "arbitration lost interrupt\n");
 		alc = priv->read_reg(priv, SJA1000_ALC);
 		priv->can.can_stats.arbitration_lost++;
-		stats->tx_errors++;
 		cf->can_id |= CAN_ERR_LOSTARB;
 		cf->data[0] = alc & 0x1f;
 	}