drm/i915/overlay: Use a continuation hook to finish work after a flip.

Slightly easier to follow than the state machine and now possible as the
control structure is opaque and hw_wedged is no longer interferred with.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 file changed