dt-bindings: drm/panel: simple: Add binding for TFC S9700RTWV43TR-01B

Add bindign for TFC S9700RTWV43TR-01B 7" Three Five Corp 800x480 LCD
panel with resistive touch.

The panel is found on TI AM335x-evm.
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/24fea39438decd1e17a9c9afa320d49aca03f60d.1553243203.git.jsarha@ti.com

Documentation/devicetree/bindings/display/panel/tfc,s9700rtwv43tr-01b.txt

+TFC S9700RTWV43TR-01B 7" Three Five Corp 800x480 LCD panel with
+resistive touch
+
+The panel is found on TI AM335x-evm.
+
+Required properties:
+- compatible: should be "tfc,s9700rtwv43tr-01b"
+- power-supply: See panel-common.txt
+
+Optional properties:
+- enable-gpios: GPIO pin to enable or disable the panel, if there is one
+- backlight: phandle of the backlight device attached to the panel
+
+This binding is compatible with the simple-panel binding, which is specified
+in simple-panel.txt in this directory.

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -406,6 +406,7 @@ technologic	Technologic Systems
 tempo	Tempo Semiconductor
 techstar	Shenzhen Techstar Electronics Co., Ltd.
 terasic	Terasic Inc.
+tfc	Three Five Corp
 thine	THine Electronics, Inc.
 ti	Texas Instruments
 tianma	Tianma Micro-electronics Co., Ltd.