media: staging: dt-bindings: rkisp1: drop parent unit address

Fix the following error found with make ARCH=arm64 dt_binding_check:

Documentation/devicetree/bindings/media/rockchip-isp1.example.dts:24.27-101.11:
Warning (unit_address_vs_reg): /example-0/parent@0: node has a unit name, but no reg or ranges property

Reported-by: Johan Jonker <jbx6244@gmail.com>
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>