platform/surface: aggregator: Make to_ssam_device_driver() respect constness

platform/surface: aggregator: Make to_ssam_device_driver() respect constness

Make to_ssam_device_driver() a bit safer by replacing container_of()
with container_of_const() to respect the constness of the passed in
pointer, instead of silently discarding any const specifications. This
change also makes it more similar to to_ssam_device(), which already
uses container_of_const().

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20230525205041.2774947-1-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>