dt-bindings: Add support for Samsung s6e3ha2 panel binding

The Samsung s6e3ha2 is a 5.7" 1440x2560 AMOLED panel connected using
MIPI-DSI interfaces.
Signed-off-by: NDonghwa Lee <dh09.lee@samsung.com>
Signed-off-by: NHyungwon Hwang <human.hwang@samsung.com>
Signed-off-by: NHoegeun Kwon <hoegeun.kwon@samsung.com>
Reviewed-by: NAndrzej Hajda <a.hajda@samsung.com>
Reviewed-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NThierry Reding <treding@nvidia.com>

Documentation/devicetree/bindings/display/panel/samsung,s6e3ha2.txt

+Samsung S6E3HA2 5.7" 1440x2560 AMOLED panel
+
+Required properties:
+  - compatible: "samsung,s6e3ha2"
+  - reg: the virtual channel number of a DSI peripheral
+  - vdd3-supply: I/O voltage supply
+  - vci-supply: voltage supply for analog circuits
+  - reset-gpios: a GPIO spec for the reset pin (active low)
+  - enable-gpios: a GPIO spec for the panel enable pin (active high)
+
+Optional properties:
+  - te-gpios: a GPIO spec for the tearing effect synchronization signal
+    gpio pin (active high)
+
+Example:
+&dsi {
+	...
+
+	panel@0 {
+		compatible = "samsung,s6e3ha2";
+		reg = <0>;
+		vdd3-supply = <&ldo27_reg>;
+		vci-supply = <&ldo28_reg>;
+		reset-gpios = <&gpg0 0 GPIO_ACTIVE_LOW>;
+		enable-gpios = <&gpf1 5 GPIO_ACTIVE_HIGH>;
+		te-gpios = <&gpf1 3 GPIO_ACTIVE_HIGH>;
+	};
+};