Lontium LT8912 MIPI-DSI to LVDS and HDMI/MHL bridge bindings

Required properties and nodes:
 - compatible: "lontium,lt8912"
 - hpd-gpios: a GPIO spec for the  hot-plug detect pin
 - port: node referencing the MIPI-DSI source
 - reg: i2c address of the bridge
 - i2c-bus: phandle of an I2C controller used for register access
 One of:
 - ddc-i2c-bus: reference to a DDC-I2C bus for EDID retrival
 - display-timings: hardcoded display timings if ddc-i2c-bus does not exist.
		    Refer to binding doc display-timing.txt for details

Optional properties:
 - reset-gpios: a GPIO spec for the reset pin

Examples:
&i2c1 {
	lt8912@48 {
		compatible = "lontium,lt8912";
		ddc-i2c-bus = <&i2c0>;
		hpd-gpios = <&gpio1 31 GPIO_ACTIVE_HIGH>;
		reg = <0x48>;

		port {
			lt8912_1_in: endpoint {
				remote-endpoint = <&mipi_dsi_bridge1_out>;
			};
		};

&i2c2 {
	lt8912@48 {
		compatible = "lontium,lt8912";
		hpd-gpios = <&gpio1 31 GPIO_ACTIVE_HIGH>;
		reg = <0x48>;

		port {
			lt8912_1_in: endpoint {
				remote-endpoint = <&mipi_dsi_bridge1_out>;
			};
		};

		display-timings {
			native-mode = <&timing0>;
			timing0: timing0 {
				clock-frequency = <74250000>;
				hactive = <1280>;
				vactive = <720>;
				hfront-porch = <110>;
				hsync-len = <40>;
				hback-porch = <220>;
				vfront-porch = <5>;
				vsync-len = <5>;
				vback-porch = <20>;
				hsync-active = <0>;
				vsync-active = <0>;
				de-active = <0>;
				pixelclk-active = <0>;
			};
		};
	};
};