dt-bindings: display: tegra: add Tegra20 VIP

VIP is the parallel video capture component within the video input
subsystem of Tegra20 (and other Tegra chips, apparently).

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>