hwmon: (via686a) Initialize fan_div values

Functions set_fan_min() and set_fan_div() assume that the fan_div
values have already been read from the register. The driver currently
doesn't initialize them at load time, they are only set when function
via686a_update_device() is called. This means that set_fan_min() and
set_fan_div() misbehave if, for example, "sensors -s" is called
before any monitoring application (e.g. "sensors") is has been run.

Fix the problem by always initializing the fan_div values at device
bind time.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>