i2c/scx200_acb: Provide more information on bus errors

Upon a bus error, it's rather hard to guess what happened. Dumping the
address, length and status provides a lot of value for troubleshooting
issues.

Signed-off-by: Willy Tarreau <wtarreau@exceliance.fr>
Signed-off-by: Jean Delvare <khali@linux-fr.org>