Is CIRRUS a suitable driver to convert to atomic mode-setting

Hi Daniel, Sorry to disturb you, I realized you are a busy man of the community. So I did some work before I email you.

I submit my proposal as you suggest, convert the two virtual driver (CIRRUS and BOCHS, if I remember it right) to atomic mode-setting.

After talked with Martin Peres(the administrator of xorg on gsoc) and Gerd Hoffmann (the author of VirtIO gpu driver), we got this question, is CIRRUS suitable to convert, as qemu using cirrus considered harmful.