dt-bindings: PCI: tegra194: Convert to json-schema

Convert the Tegra194 PCIe bindings from the free-form text format to
json-schema.

Link: https://lore.kernel.org/r/20220721142052.25971-2-vidyas@nvidia.com


Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>