Remove legacy usage of drm_handle_vblank()
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1467677092-5089-3-git-send-email-gustavo@padovan.org