arm64: dts: rockchip: add fuel gauge to Pinebook Pro dts

This commit adds cw2015 fuel gauge and battery to the Pinebook Pro dts.

Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Link: https://lore.kernel.org/r/20200528172550.2324722-2-t.schramm@manjaro.org


Signed-off-by: Heiko Stuebner <heiko@sntech.de>