sunxi: DT: add support for Pinebook

Pinebook is a laptop produced by Pine64, with USB-connected keyboard,
USB-connected touchpad and an eDP LCD panel connected via a RGB-eDP
bridge from Analogix.

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Vagrant Cascadian <vagrant@debian.org>
Reviewed-by: Jagan Teki <jagan@openedev.com>