Add tiled based ad-hoc damage detection for matrox like GPUs
We want to avoid posting damage as much as possible when using GPUs like matrox. In Xorg, there are some logic that splits up the screen into "tiles" and checks whether they changed or not, adding this to the regions that are eventually copied over to the onscreen framebuffer from the offscreen shadow buffer.
To be on par, we might need to do something similar in mutter.