dt-bindings: display: tegra: Convert to json-schema

Convert the Tegra host1x controller bindings from the free-form text
format to json-schema.

This also adds the missing display-hub DT bindings that were not
previously documented.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-epp.yaml

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/tegra/nvidia,tegra20-epp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra Encoder Pre-Processor
+
+maintainers:
+  - Thierry Reding <thierry.reding@gmail.com>
+  - Jon Hunter <jonathanh@nvidia.com>
+
+properties:
+  $nodename:
+    pattern: "^epp@[0-9a-f]+$"
+
+  compatible:
+    enum:
+      - nvidia,tegra20-epp
+      - nvidia,tegra30-epp
+      - nvidia,tegra114-epp
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    items:
+      - description: module reset
+
+  reset-names:
+    items:
+      - const: epp
+
+  iommus:
+    maxItems: 1
+
+  interconnects:
+    maxItems: 4
+
+  interconnect-names:
+    maxItems: 4
+
+  operating-points-v2:
+    $ref: "/schemas/types.yaml#/definitions/phandle"
+
+  power-domains:
+    items:
+      - description: phandle to the core power domain
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/tegra20-car.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    epp@540c0000 {
+        compatible = "nvidia,tegra20-epp";
+        reg = <0x540c0000 0x00040000>;
+        interrupts = <GIC_SPI 70 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&tegra_car TEGRA20_CLK_EPP>;
+        resets = <&tegra_car 19>;
+        reset-names = "epp";
+    };