V4L/DVB (11608): soc-camera: host-driver cleanup

Embed struct soc_camera_host in platform-specific per host instance objects
instead of allocating them statically in drivers, use platform_[gs]et_drvdata
consistently, use resource_size().

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