i386: Rename bools in PCMachineState to end in _enabled

i386: Rename bools in PCMachineState to end in _enabled

This makes their function more clear and prevents conflicts when adding
the actual devices to the machine state, if necessary.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20181107152434.22219-1-minyard@acm.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>