arm64: dts: rockchip: rock5b: enable vsync debug gpio

Enable toggling GPIO for outgoing video frames on the first
video output port for latency debugging.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

arch/arm64/boot/dts/rockchip/rk3588-rock-5b-imx415.dtsi

@@ -154,3 +154,7 @@ isp0_vir0: endpoint@0 {
 		};
 	};
 };
+
+&vp0 {
+	vsync-notify-gpios = <&gpio3 RK_PC3 GPIO_ACTIVE_HIGH>; /* pin 7 on pin header */
+};