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 <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Eduardo Habkost <[email protected]>
Message-Id: <20181107152434[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Tested-by: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Eduardo Habkost <[email protected]>