V4L/DVB (8610): Add suspend/resume capabilities to soc_camera.

Add suspend/resume hooks to call soc operation specific
suspend and resume functions. This ensures the camera
chip has been previously resumed, as well as the camera
bus.
These hooks in camera chip drivers should save/restore
chip context between suspend and resume time.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>