hwmon: (max1668) Fix writing the minimum temperature

commit 500a91571f0a5d0d3242d83802ea2fd1faccc66e upstream.

When trying to set the minimum temperature, the driver was erroneously
writing the maximum temperature into the chip.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>