can: bittiming: can_fixup_bittiming(): use CAN_SYNC_SEG instead of 1

Commit 1c47fa6b ("can: dev: add a helper function to calculate the
duration of one bit") made the constant CAN_SYNC_SEG available in a
header file.

The magic number 1 in can_fixup_bittiming() represents the width of
the sync segment, replace it by CAN_SYNC_SEG to make the code more
readable.

Link: https://lore.kernel.org/all/20230202110854.2318594-3-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/dev/bittiming.c

@@ -39,7 +39,7 @@ static int can_fixup_bittiming(const struct net_device *dev, struct can_bittimin
 		return -EINVAL;
 
 	bt->bitrate = priv->clock.freq / (bt->brp * can_bit_time(bt));
-	bt->sample_point = ((tseg1 + 1) * 1000) / can_bit_time(bt);
+	bt->sample_point = ((CAN_SYNC_SEG + tseg1) * 1000) / can_bit_time(bt);
 
 	return 0;
 }