machine: Remove unused fields from QEMUMachine

machine: Remove unused fields from QEMUMachine

This removes the following fields from QEMUMachine: family, alias,
reset, hot_add_cpu, units_per_default_bus, no_serial, no_parallel,
use_virtcon, use_sclp, no_floppy, no_cdrom, default_display,
compat_props, and hw_version.

The only users of those fields were already converted to use QOM and
MachineClass directly, so they are not needed anymore.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>