[PATCH] drm/rockchip: remove atomic helper dirtyfb

The blocking implementation of the dirtyfb ioctl is extremely slow when used for damage tracking on RK3399. If this implementation is in place Xorg will default to using it and will slow down considerably when doing a lot of small draws. This is most apparent with the fvwm window manager on startup where it will almost lock up for many seconds seconds on RK3399.

Removing this implementation did not cause any visible issues on RK3399 but it did fix the performance issues on Xorg as it will disable damage tracking when the ioctl returns it's not supported.