can: dev: register_candev(): bail out if both fixed bit rates and bit timing constants are provided

The CAN driver framework supports either fixed bit rates or bit timing
constants. Bail out during driver registration if both are given.

Link: https://lore.kernel.org/all/20230202110854.2318594-7-mkl@pengutronix.deSigned-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/dev/dev.c

@@ -530,6 +530,11 @@ int register_candev(struct net_device *dev)
 	if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
 		return -EINVAL;
 
+	/* We only support either fixed bit rates or bit timing const. */
+	if ((priv->bitrate_const || priv->data_bitrate_const) &&
+	    (priv->bittiming_const || priv->data_bittiming_const))
+		return -EINVAL;
+
 	if (!can_bittiming_const_valid(priv->bittiming_const) ||
 	    !can_bittiming_const_valid(priv->data_bittiming_const))
 		return -EINVAL;