soc-camera: unify i2c camera device platform data

Unify i2c camera device platform data to point to struct soc_camera_link
for a smooth transition to soc-camera as a platform driver.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>