hw: fix using 4.2 compat in 5.0 machine types for i440fx/q35

hw: fix using 4.2 compat in 5.0 machine types for i440fx/q35

5.0 machine type uses 4.2 compats. This seems to be incorrect, since
the latests machine type by now is 5.0 and it should use its own
compat or shouldn't use any relying on the defaults.
Seems, like this appeared because of some problems on merge/rebase.

Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20191223072856.5369-1-dplotnikov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>