arm64: tegra: Add GPCDMA node for tegra186 and tegra194

Add device tree node for GPCDMA controller on Tegra186 target
and Tegra194 target.

Signed-off-by: Rajesh Gumasta <rgumasta@nvidia.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>