V4L/DVB (13650): soc-camera: switch drivers and platforms to use .priv in struct soc_camera_link

After this change drivers can be further extended to not fail, if they don't
get platform data, but to use defaults.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>