arm64: dts: rockchip: add generic pinconfig settings used by most Rockchip socs

The pinconfig settings for Rockchip SoCs are pretty similar on all socs,
so move them to a shared dtsi to be included, instead of redefining them
for each soc.

Signed-off-by: Liang Chen <cl@rock-chips.com>
Link: https://lore.kernel.org/r/20210622020517.13100-3-cl@rock-chips.com


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