media: v4l2-core: Introduce v4l2-isp.c

media: v4l2-core: Introduce v4l2-isp.c

Add to the V4L2 framework helper functions to support drivers when
validating a buffer of V4L2 ISP parameters.

Driver shall use v4l2_isp_params_validate_buffer_size() to verify the
size correctness of the data received from userspace, and after having
copied the data to a kernel-only memory location, complete the
validation by calling v4l2_isp_params_validate_buffer().

Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Michael Riesch <michael.riesch@collabora.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>