dt-bindings: input: touchscreen: add compatible string for Goodix GT917S

Goodix GT917S is a new touchscreen chip from Goodix.

Add its compatible string to the device tree binding.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Bastien Nocera <hadess@hadess.net>
Link: https://lore.kernel.org/r/20200228010146.12215-2-icenowy@aosc.ioSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/touchscreen/goodix.yaml

@@ -21,6 +21,7 @@ properties:
       - goodix,gt911
       - goodix,gt9110
       - goodix,gt912
+      - goodix,gt917s
       - goodix,gt927
       - goodix,gt9271
       - goodix,gt928