hwmon: (dell-smm) Cleanup init code

The default values for i8k_fan_mult and i8k_fan_max
should be assigend only if the values specified as
module params or in DMI are invalid/missing.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20220426213154.724708-3-W_Armin@gmx.de


Signed-off-by: Guenter Roeck <linux@roeck-us.net>