[media] V4L: ov5642: remove superfluous soc-camera client operations

Now that all soc-camera hosts have been ported to use V4L2 subdevice
mediabus-config operations and soc-camera client bus-parameter operations
have been made optional, they can be removed.

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