media: staging: media: rkisp1: make links immutable by default

The only places which make sese to allow users to enable or disable
links are:

* between sensors and isp:
So users can select which sensor should be used while streaming

* between isp and the resizers:
              |
              v here
rkisp1_isp:2 -> rkisp1_resizer_mainpath -> rkisp1_mainpath (capture)
            \-> rkisp1_resizer_selfpath -> rkisp1_selfpath (capture)
              ^ here
              |

So users can disable one of the capture paths when unused, to avoid
worring about matching formats.

Make the following links immutable to simplify userspace:

rkisp1_resizer_mainpath -> rkisp1_mainpath
rkisp1_resizer_selfpath -> rkisp1_selfpath
rkisp1_params           -> rkisp1_isp
rkisp1_isp              -> rkisp1_stats

Signed-off-by: Helen Koike <helen.koike@collabora.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>