hwmon: (nct6775) Swap STEP_UP_TIME and STEP_DOWN_TIME registers for most chips

The STEP_UP_TIME and STEP_DOWN_TIME registers are swapped for all chips but
NCT6775.

Reported-by: Grazvydas Ignotas <notasas@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Guenter Roeck <linux@roeck-us.net>