platform/surface: aggregator_registry: Add support for tablet-mode switch on Surface Pro 9

Add support for the POS-subsystem tablet-mode switch used on the Surface
Pro 9.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20230304194611.87770-4-luzmaximilian@gmail.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/surface/surface_aggregator_registry.c

@@ -305,7 +305,7 @@ static const struct software_node *ssam_node_group_sp9[] = {
 	&ssam_node_bat_ac,
 	&ssam_node_bat_main,
 	&ssam_node_tmp_pprof,
-	/* TODO: Tablet mode switch (via POS subsystem) */
+	&ssam_node_pos_tablet_switch,
 	&ssam_node_hid_kip_keyboard,
 	&ssam_node_hid_kip_penstash,
 	&ssam_node_hid_kip_touchpad,