hwmon: (w83l786ng) Report correct minimum fan speed

Current code is buggy, it shows the current fan speed as minimum fan speed.
Fix up show_fan_reg macro to correctly report fan and fan_min speed.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Kevin Lo <kevlo@kevlo.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>