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>;
					};
				};
			};
		};
	};