[drm-modesetting] optional connector properties, share your thoughts

[Maarten Maathuis]

I've been reviewing the kernel modesetting interfaces while they are
not yet set in stone. Since consistent properties are desirable we
must standardise on several optional, but common properties.

scaling_mode:
- panel <-- this name is debateble, it means native mode is ignored
- fullscreen
- noscale
- aspect

dithering: variable dithering needed?
- on
- off

Please share your thought about these properties and others you deem
neccesary, especially if you're a potentional driver writer.

Maarten.