PiCam unusable via V4l2

[Anton Ivanov]

1. Camera can be opened only once (and not every time) upon boot using the v4l2 driver
2. Camera cannot be closed correctly - motion and other v4l2 report errors on closing.
3. Camera cannot be re-opened - motion cannot be restarted
4. Camera kernel driver cannot be removed and reinserted.

Overall - the v4l2 driver for the onboard camera interface is broken across the board in jessie.

Tested with

Pi Model B, B+ and Pi model 3, two different cameras and different cables so this does not look like a hardware problem specific to one module/board.