add support for atomic mode setting, planes, properties and multi pane framebuffer

[tauu]

This PR adds the ioctl apis required to use

• multi bit plane framebuffers
• planes
• properties
• atomic modesetting

The apis are implemented in the same way as the existing ioctl api calls. Input/output data structures for the new ioctl apis have been added as well as functions converting common go types to these data structure and executing the syscall.

[i4ki]

Hi @tauu

The code looks promising but in order to make it easier to test if everything works, would be nice if you can add an example to this directory.

This project is unmaintained at the moment and it's being a long time since I did this library, so I recommend you maintaining your own fork of it until I refresh my knowledge about the DRM API and can wrap my head around your changes, and why they are important. If you provide some example code using them, it will make my life easier.