V4L/DVB (9785): soc-camera: merge .try_bus_param() into .try_fmt_cap()

.try_bus_param() method from struct soc_camera_host_ops is only called at one
location immediately before .try_fmt_cap(), there is no value in keeping these
two methods separate, merge them.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>