V4L/DVB (8342): sh_mobile_ceu_camera: Add SuperH Mobile CEU driver V3

This is V3 of the SuperH Mobile CEU soc_camera driver.

The CEU hardware block is configured in a transparent data fetch
mode, frames are captured from the attached camera and written to
physically contiguous memory buffers provided by the newly added
videobuf-dma-contig queue. Tested on sh7722 and sh7723 processors.

 Changes since V2:
 - remove SUPERH Kconfig dependency
 - move sh_mobile_ceu.h to include/media
 - add board callback support with enable_camera()/disable_camera()
 - add support for declare_coherent_memory
 - rework video memory limit
 - more verbose error messages

 Changes since V1:
 - fixed the CEU driver to work with the newly updated patches

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>