dt-bindings: display: sitronix, st7735r: Make reset-gpios optional

There are other ways than using a gpio to reset the controller so make
this property optional.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: David Lechner <david@lechnology.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211124150757.17929-3-noralf@tronnes.org

Documentation/devicetree/bindings/display/sitronix,st7735r.yaml

@@ -48,7 +48,6 @@ required:
   - compatible
   - reg
   - dc-gpios
-  - reset-gpios
 
 additionalProperties: false