dt-bindings: phy: add Amlogic G12A Analog MIPI D-PHY bindings

The Amlogic G12A SoCs embeds an Analog MIPI D-PHY to communicate with DSI
panels, this adds the bindings.

This Analog D-PHY works with a separate Digital MIPI D-PHY.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220705075650.3165348-2-narmstrong@baylibre.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/amlogic,g12a-mipi-dphy-analog.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/phy/amlogic,g12a-mipi-dphy-analog.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Amlogic G12A MIPI analog PHY
+
+maintainers:
+  - Neil Armstrong <narmstrong@baylibre.com>
+
+properties:
+  compatible:
+    const: amlogic,g12a-mipi-dphy-analog
+
+  "#phy-cells":
+    const: 0
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    phy@0 {
+          compatible = "amlogic,g12a-mipi-dphy-analog";
+          reg = <0x0 0xc>;
+          #phy-cells = <0>;
+    };