media: atomisp: Remove atomisp_file_fops and atomisp_file_ioctl_ops

After the file-injection support removal, atomisp_video_pipe->type never
is V4L2_BUF_TYPE_VIDEO_OUTPUT anymore, so the V4L2_BUF_TYPE_VIDEO_OUTPUT
support path in atomisp_video_init() is never hit and this path is
the only user of atomisp_file_fops and atomisp_file_ioctl_ops.

Remove atomisp_file_fops and atomisp_file_ioctl_ops and all of
the functions which are only referenced by these ops structs.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>