devicetree/bindings: add reset-gpios and vcc-supply for panel-dpi

Some displays have a reset input and/or need a regulator to function
properly. Allow to specify them for panel-dpi devices.
Acked-by: NRob Herring <robh@kernel.org>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Documentation/devicetree/bindings/display/panel/panel-dpi.txt

@@ -7,6 +7,8 @@ Required properties:
 Optional properties:
 - label: a symbolic name for the panel
 - enable-gpios: panel enable gpio
+- reset-gpios: GPIO to control the RESET pin
+- vcc-supply: phandle of regulator that will be used to enable power to the display
 
 Required nodes:
 - "panel-timing" containing video timings