dt-bindings: PCI: Add PCI Endpoint Controller Schema

Define a common schema for PCI Endpoint Controllers.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/pci-ep.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/pci-ep.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: PCI Endpoint Controller Schema
+
+description: |
+  Common properties for PCI Endpoint Controller Nodes.
+
+maintainers:
+  - Kishon Vijay Abraham I <kishon@ti.com>
+
+properties:
+  $nodename:
+    pattern: "^pcie-ep@"
+
+  max-functions:
+    description: Maximum number of functions that can be configured
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint8
+    minimum: 1
+    default: 1
+    maximum: 255
+
+  max-link-speed:
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [ 1, 2, 3, 4 ]
+
+  num-lanes:
+    description: maximum number of lanes
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1
+    default: 1
+    maximum: 16
+
+required:
+  - compatible