mddi/hvga: Remove DBC mode control

It's only supported by 2 panels and it needs more userspace stuff
to make it configurable. Leave it in video mode by default like sony did

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>
mddi/hvga: Remove more unused code

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>
novatek: Cleanup ifdefs & unused code

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>