media: v4l2-ioctl: Access v4l2_fh from private_data

media: v4l2-ioctl: Access v4l2_fh from private_data

Now that it is guaranteed that file->private_data is set to point to the
'struct v4l2_fh' initialised by v4l2_fh_add() the v4l2-ioctl layer can
be modified to retrieve the v4l2_fh pointer from the file *.

As the __video_do_ioctl() function, that calls all the handlers modified
by this patch goes as:

static long __video_do_ioctl(struct file *file,
		unsigned int cmd, void *arg)
{
	void *fh = file->private_data;

	...

	ret = info->func(ops, file, fh, arg);

}

This patch introduces no functional changes and makes it possible to
remove in future the 'fh' argument to all ioctl handlers.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>