dt-bindings: Add Truly NT35597 panel driver bindings

Truly model NT35597 DSI display driver

The Truly NT35597 is a generic display driver, currently only configured

for use in the 2K display on the Qualcomm SDM845 MTP board.

Required properties:

- compatible: should be "truly,nt35597-2K-display"

- vdda-supply: phandle of the regulator that provides the supply voltage

  Power IC supply

- vdispp-supply: phandle of the regulator that provides the supply voltage

  for positive LCD bias

- vdispn-supply: phandle of the regulator that provides the supply voltage

  for negative LCD bias

- reset-gpios: phandle of gpio for reset line

  This should be 8mA, gpio can be configured using mux, pinctrl, pinctrl-names

  (active low)

- mode-gpios: phandle of the gpio for choosing the mode of the display

  for single DSI or Dual DSI

  This should be low for dual DSI and high for single DSI mode

- ports: This device has two video ports driven by two DSIs. Their connections

  are modeled using the OF graph bindings specified in

  Documentation/devicetree/bindings/graph.txt.

  - port@0: DSI input port driven by master DSI

  - port@1: DSI input port driven by secondary DSI

Example:

	dsi@ae94000 {

		panel@0 {

			compatible = "truly,nt35597-2K-display";

			reg = <0>;

			vdda-supply = <&pm8998_l14>;

			vdispp-supply = <&lab_regulator>;

			vdispn-supply = <&ibb_regulator>;

			pinctrl-names = "default", "suspend";

			pinctrl-0 = <&dpu_dsi_active>;

			pinctrl-1 = <&dpu_dsi_suspend>;

			reset-gpios = <&tlmm 6 GPIO_ACTIVE_LOW>;

			mode-gpios = <&tlmm 52 GPIO_ACTIVE_HIGH>;

			ports {

				#address-cells = <1>;

				#size-cells = <0>;

				port@0 {

					reg = <0>;

					panel0_in: endpoint {

						remote-endpoint = <&dsi0_out>;

					};

				};

				port@1 {

					reg = <1>;

					panel1_in: endpoint {

						remote-endpoint = <&dsi1_out>;

					};

				};

			};

		};

	};