arm64: dts: rockchip: Add Xunlong OrangePi R1 Plus LTS

The OrangePi R1 Plus LTS is a minor variant of OrangePi R1 Plus with
the on-board NIC chip changed from rtl8211e to yt8531c, and otherwise
identical to OrangePi R1 Plus.

Signed-off-by: Tianling Shen <cnsztl@gmail.com>
Link: https://lore.kernel.org/r/20230325074022.9818-5-cnsztl@gmail.com


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