[media] V4L: soc-camera: remove soc-camera bus and devices on it

Now that v4l2 subdevices have got their own device objects, having
one more device in soc-camera clients became redundant and confusing.
This patch removes those devices and the soc-camera bus, they used to
reside on.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>