media: staging: dt-bindings: rkisp1: drop i2c unit address

Add missing required items in Rockchip ISP1 dt-bindings example for
a complete i2c node.
Drop unit address to Fix error:
/example-0/parent/i2c@ff160000: node has a unit name, but no reg or ranges property
Remove unecessary fields for the example.

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>