dt-bindings: Add headers for NVDEC on Tegra234

Add clock, memory controller, powergate and reset dt-binding headers
necessary for NVDEC.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>