A mirror-less camera is generally a thinner camera than d-slr which may mean the lens mount would put the rear element of a lens much closer to the sensor than on d-slr bodies. this means new lenses are need that are able to focus properly on the sensor. and if an EF lens was mounted to it, it would be trying to focus on a sensor that is further back than on the mirror-less sensor. so what are the chances of a new mount system, new lenses, but with the same EF technology. This would allow for an adaptor to be released that would simply pull the ef lenses further from the sensor, to be able to focus correctly, and still be able to AF and control F-stop.
made a little picture of my thought