convert ad-hoc way we use to generate AML for ISA/SMB IPMI devices
to a generic approach (i.e. make devices provide its own AML blobs
like it is done with other ISA devices (ex. KBD))

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20220608135340.3304695-17-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>