s390x/event-facility: Simplify sclp_get_event_facility_bus()

sclp_get_event_facility_bus() scans the whole machine to find a
TYPE_SCLP_EVENTS_BUS object. The SCLPDevice instance is now available
under the machine state, use it to simplify the lookup and adjust the
creation of the consoles.

Signed-off-by: Cédric Le Goater <clg@redhat.com>
Message-ID: <20240502131533.377719-3-clg@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
3 files changed