hwmon: (dell-smm) Move clamping of fan speed out of i8k_set_fan()

hwmon: (dell-smm) Move clamping of fan speed out of i8k_set_fan()

Currently i8k_set_fan() clamps the fan speed before performing the
SMM call to ensure that the speed is not negative and not greater than
i8k_fan_max. This however is mostly unnecessary as the hwmon and
thermal interfaces alread ensure this. Only the legacy ioctl interface
does not ensure that the fan speed passed to i8k_set_fan() does meet
the above criteria.

Move the clamping out of i8k_set_fan() and into the legacy ioctl
handler to prepare for future changes.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20250917181036.10972-3-W_Armin@gmx.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>