platform/surface: aggregator_registry: Use generic client removal function

Use generic client removal function introduced in the previous commit
instead of defining our own one.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20211028002243.1586083-3-luzmaximilian@gmail.com


Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>