drm/rockchip: Use dirtyfb helper

Instead of flushing all vops every time we get a dirtyfb call, use the
damage helper to kick off an atomic commit. Even though we don't use
damage clips, the helper commit will force us through the normal
psr_inhibit_get/put sequence.

Changes in v3:
- Added to the set
Changes in v4:
- None
Changes in v5:
- None

Link to v3: https://patchwork.freedesktop.org/patch/msgid/20190502194956.218441-7-sean@poorly.run
Link to v4: https://patchwork.freedesktop.org/patch/msgid/20190508160920.144739-7-sean@poorly.run



Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611160844.257498-7-sean@poorly.run