MAINTAINERS: Update IRC link for Surface System Aggregator subsystem

We have moved to libera.chat. Update the link accordingly.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210614194635.1681519-1-luzmaximilian@gmail.com


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