Remove some unneded, empty code and set user_creatable to false
(besides being not implemented yet, so does nothing anyway) it's also
normally part of VIA south bridge chips so no need to confuse users
showing them these devices.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <c7a5b1ee4c02e304ff70ebfbf269544f3c1f8412.1609584216.git.balaton@eik.bme.hu>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>