Log Message:
u-boot-nanopi-r2s: add new package

This has been tested by myself and found to work seemingly stably,
including the RTL8153 USB-based Ethernet port (which was reported to
have issues on port-arm@ back in 2022).

This package is not based on the one in wip, as it was very out of date
and was reported to support less of the hardware correctly. Instead,
the more current framework for Rockchip boards in pkgsrc is used.