platform/surface: aggregator_registry: add entry for fan speed

Add an entry for the fan speed function.
Add this new entry to the Surface Pro 9 group.

Signed-off-by: Ivor Wanders <ivor@iwanders.net>
Link: https://github.com/linux-surface/kernel/pull/144


Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20240131005856.10180-3-ivor@iwanders.net


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>