hwmon: (dell-smm) Add support for automatic fan mode

hwmon: (dell-smm) Add support for automatic fan mode

Many machines treat fan state 3 as some sort of automatic mode,
which is superior to the separate SMM calls for switching to
automatic fan mode for two reasons:

- the fan control mode can be controlled for each fan separately
- the current fan control mode can be retrieved from the BIOS

On some machines however, this special fan state does not exist.
Fan state 3 acts like a regular fan state on such machines or
does not exist at all. Such machines usually use separate SMM calls
for enabling/disabling automatic fan control.

Add support for it. If the machine supports separate SMM calls
for changing the fan control mode, then the other interface is
ignored.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20250917181036.10972-4-W_Armin@gmx.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>