Add support for the sink pad of scaler subdevice to respond
VIDIOC_G_SELECTION and VIDIOC_S_SELECTION ioctls with the following
targets: V4L2_SEL_TGT_COMPOSE_BOUNDS and V4L2_SEL_TGT_CROP.

* Add new const struct crop_rect_default to initialize subdev scaler
  properly.
* Make changes in sink pad format reflect to the crop rectangle. E.g.
  changing the frame format to a smaller size one can make the former
  crop rectangle selects a non existing frame area. To solve this
  situation the crop rectangle is clamped to the frame boundaries.
* Clamp crop rectangle respecting the sink bounds during set_selection
  ioctl.
Co-developed-by: Danilo Figueiredo Rocha <drocha.figueiredo@gmail.com>
Signed-off-by: Guilherme Alcarde Gallo <gagallo7@gmail.com>
Signed-off-by: Danilo Figueiredo Rocha <drocha.figueiredo@gmail.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>