arm64: allwinner: a64: enable LCD-related hardware for Pinebook

Pinebook has an ANX6345 bridge connected to the RGB666 LCD output and
eDP panel input. The bridge is controlled via I2C that's connected to
R_I2C bus.

Enable all this hardware in device tree.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>