The EGL platform might go away at any time through reconfiguration or because
of a graphic error. KWin then resets the graphics. The dmabuf implementation
must respect that and recover from a graphics reset by recreating all EGL
images for existing buffer.
This assumes that we won't change our graphics API mid-session and that
supported plane and modifier configuration stays constant.
In practise we remember all current dmabufs in a single map and only remove
them if the client did destroy the resource.