V4L/DVB (11024): soc-camera: separate S_FMT and S_CROP operations

As host and camera drivers become more complex, differences between S_FMT and
S_CROP functionality grow, this patch separates them.

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