aspeed: Clean up roundabout error propagation

aspeed: Clean up roundabout error propagation

Replace

        sysbus_realize(SYS_BUS_DEVICE(&s->spi[i]), &local_err);
        error_propagate(&err, local_err);
        if (err) {
            error_propagate(errp, err);
            return;
	}

by

        sysbus_realize(SYS_BUS_DEVICE(&s->spi[i]), &err);
        if (err) {
            error_propagate(errp, err);
            return;
	}

Cc: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20200630090351.1247703-13-armbru@redhat.com>